Hi,

I am facing a weird computer problem. Until recently my computer was working all right.
Now when I try to switch it on the Power LED comes on and stays on as it should, the keyboard LEDs blink and processor and SMPS fans go on (I have opened the cabinet and checked). The DVD-RW blinks indicating power to it. However there is no 'beep' from the system speaker. I have tried removing and re connecting all power and data cables. I have tried removing the RAM and then trying to boot, there is still o beep. I have tried disconnectig each of the HDD, and DVD and then tried booting and there is still no beep. The system does not start up and I might hae to switch of all the power and wait for maybe 6-10 hours and then try again.

The system does start up from time to time, works fine and then the mouse cursor tends to go into 'waiting hourglass' and then when I switch it off and on it doesn't go on.

I have recently installed a new HDD but also have an old one.

However on other times the system switches on just fine.

I am using the following config:
P4 1.6GHz
256 MB RAM DDR1 Dyenet(192+64 shared)
160 GB Seagate Barracuda.
Sony DVD-RW G120A

I would appreciate any suggestion. Thanks in advance.

I have also tried another working SMPS and the problem still remains.

A system won't boot without RAM, but you *should* have gotten a constant beep code indicating that no RAM is present.

What about dust buildup within the case...especially on the heatsinks, fans & inside the power supply? Make sure they are all dust free.

It could be your power supply is failing. It's possible that it's putting out enough power to spin some fans & flash a few LEDs, but not enough to boot an entire system. Try temporarily disconnecting all data & power cables to the HDD, optical drives, floppy, etc...this will lighten the load on the PSU. Then see if it'll boot & show a display on your screen.

One thing that stands out about your specs is the RAM amount..."192+64 shared"? Your system must be horribly slow.

"I have also tried another working SMPS and the problem still remains"

Being that you call the power supply an "SMPS", it leads me to believe that you're from India? Judging from past posts from people in that part of the world, the PSU (Power Supply Unit) choices aren't very good. Most of them downright suck & the good ones are extremely expensive.

Well jam thanks for the respnses. I am from India.

I have tried booting the system with no connections at all except for the two to the mothertboard. Still there is no beep. As regards the power supply I have tried a new working Power Supply but it didn't help.

"I have tried a new working Power Supply"

PSU of at least 350W & 16A or more on the +12v rail?

When a power supply fails, it is unfortunately random whether it will damage something else while failing. If the PS is an el-cheapo, it is a lot more likely to damage something else while failing, often the mboard, but any PS can damage something else, and in that case trying a known good PS won't restore the computer to a working condition.
What is the make and model of the original PS?

Check your original PS.
The second PS must have the same wiring to it's main connector and other connectors.
See response 4 in this:
http://www.computing.net/hardware/w...

The fact you get no beep after connecting the second PS is not a good sign.
If the cpu fan is spinning okay and it and it's heatsink are not excessively filthy or clogged with mung, the most likely thing is your mboard is fried, either because of the PS failing or for some other reason.

There is a small chance your mboard has the bad capacitor problem.

Examine the mboard to see if you have bad capacitors, and/or other findable signs of mboard damage .

This was the original bad capacitor problem - has some example pictures.
History of why the exploding capacitors and which mboard makers were affected:
http://members.datafast.net.au/~dft...

What to look for, mboard symptoms, example pictures:
http://www.badcaps.net/pages.php?vid=5
Home page that site
- what the problem is caused by
- he says there are STILL bad capacitors on more recent mboards.
http://www.badcaps.net/

Pictures of blown capacitors, other components, power supplies, Athlon cpu's, etc.:
http://www.halfdone.com/Personal/Jo...
......

All desktop computer PSs are SMPSs - Switching Mode Power Supplies. Since they all use switching mode, the SM is often omitted when refering to them.
They use a IC to control switching circuits in order to step down the 240 volt or 120 volt AC to a smaller AC value that can be easily converted (regulated and rectified) to + and - 12v DC, eliminating the need for a large expensive conventional transformer. The tranformers in the PS are for stepping down the AC voltage the switching circuits provides to lesser AC values suitable to be converted to + and - 5v DC and + 3.3v DC only.

PSU of at least 350W & 16A or more on the +12v rail?

My original Power Supply is 250W and 9A on 12V - Mercury (Kobian) brand. The other one I think was with a higher power rating.

I did check the capacitors. There is no leakage or any bad capacitors. The board is around a year old as is the RAM. I did have a recent problem with the RAM and got it replaced. The processor and PS are about 4 years old. My previous board had burnt out from the power connector on the motherboard.

What I really cant understand is the intermittent times when the computer does start up. I also remember that when this problem started my comp used to work fine when on, but there were issues starting it up once it was shut down and left off for a while. This was about 20 days back. I had left my comp on with occasional restarts for a period of about 10 days.

I have cleant out the heat sink and the board yesterday for all dust. Can't figure out how to open the PS though.

One more thing I do check the voltages in the BIOS from time to time and all voltages 12V, 5V and 3.3V are all generally just *below* 12, 5 and 3.3.

And assuming the PS I am currently using is a poor one ow would I know a good brand (besides warranty)?

"My original Power Supply is 250W and 9A on 12V - Mercury (Kobian) brand."

Your mboard is relatively old. 250 watts may be fine if it is a good quality PS, but at least 300 watts would be a better minumum.

However, that PS appears to be an el-cheapo.
At present, these websites do not work for me:
http:// www.kobian.com
http://www.mercury-pc.com
This works, but the link in it to www.mercury-pc.com doesn't work:
http://www.kobian-usa.com/
There is a Canadian site but it has only Mercury cameras.

I found some "hits" on Ebay, for Mercury cases with Mercury PSs - starting at $21 AUS - not a good sign - too cheap.

Apparently Kobian makes Mercury products and is based in India.

How do you tell whether a PS is likely a good one?
1. If it's extremely cheap, cheaper than many others of the same capacity, it's probably one you should avoid buying. If you buy a case with an included PS, bare minimum it should cost you $60 or more.
2. It's brand should be one that is recognized as making reliable PSs. If you don't know yourself, look on the web, or ask someone who should know, such as someone who repairs computers, not necessarily someone who is trying to sell you a PS.
3. The maker should have a web site that is functional and reasonable and has reasonable info and specs on it about your PS, including a clear statement of what it's warranty period is.
If there is no web site, or the web site is not functional or not fully functional, or the web site has very little info about your PS model, don't buy it.
4. If the warranty is not stated anywhere, or if it is but is only 90 days or less than a year, don't but it. Good quality PSs makers will have PS warranties of at least a year, better still 3 years, or lifetime.
5. It should be stated it has anti-short and overvoltage protection, that shuts off the PS if either of those events happen before it damages the mboard or other components connected to the mboard.
6. If you can compare PSs of the same capacity by physically looking at and handling them
- el-cheapo PSs use the minimum components they can get away with, and they are usually lighter overall - a better PS is often much heavier than an el-cheapo.
- many el-cheapo PSs have one fan. Many better ones have two.
- the fan(s) in el-cheapo PSs may not have ball bearings on one or both sides - better PSs have fans with ball bearings both sides, or ceramic bearings. You might be able to determine that from the label on the fan (e.g. sleeve bearings or nothing about bearings (no ball bearings), or ball bearings (note the S - two sides), not ball bearing (one side, the other is sleeve),
or from the PSs specs.
7. If several of the above are iffy, they're probably lying about max capacities, etc. Don't buy it.

Your Mercury PS at the very least is definately extremely cheap, I haven't found any easy to find info it's considered a reliable brand, and at present does not a functional web site - I can't comment on the other stuff without a functional web site.
I certainly wouldn't buy one.

"I did have a recent problem with the RAM and got it replaced."

"Bad" ram is extremely rare, unless it is the rare case it was damaged by some device or event external to it, such as a power supply failing, or a voltage surge or spike the computer wasn'r protected against.
The vast majority of the time, either you were trying to use ram that wasn't compatible with the mboard's chipset (if it never worked properly), or you have a poor connection in the ram slots problem (if it worked properly previously).
Trying ram in this mboard that works in another mboard , or trying any ram you buy or have lying around, may not work - it has to be compatible with the mboard and it's chipset.

See response 5 in this for some info about ram compatibilty, and some places where you can find out what will work in your mboard for sure:
http://www.computing.net/hardware/w...
Correction to that:
Mushkin www.mushkin.com

A common thing that can happen with ram, even ram that worked fine previously, is the ram has, or has developed, a poor connection in it's slot(s).
This usually happens a long time after the ram was installed, but it can happen with new ram, or after moving the computer case from one place to another, and I've had even new modules that needed to have their contacts cleaned.

See response 2 in this - try cleaning the contacts on the ram modules, and making sure the modules are properly seated:
http://www.computing.net/hardware/w...

If you run a ram test
- do that AFTER cleaning the contacts on the ram modules, and making sure the modules are properly seated, otherwise any errors found are probably INVALID.
- if the ram you are trying to use is incompatible with the mboard chipset, it will likely FAIL a ram test - that is also an INVALID result.
- make sure it is the most recent version available - some older versions cannot test newer ram types properly.

"My previous board had burnt out from the power connector on the motherboard."

Connectors don't burnt out spontaneously. The most likely cause of that, other than a mistake made by the user, or a voltage surge or spike the computer wasn't protected against, and/or a lightning strike on your power grid somewhere near you, is a defective PS failing, or in a small number of cases the bad capacitor problem .

" What I really cant understand is the intermittent times when the computer does start up."
"...there were issues starting it up once it was shut down and left off for a while. "

You didn't mention that before.
That can easily be caused by a defective PS, or a poor connection of all sorts.
Failing power supplies are common and can cause your symptoms.
Check your PS.
See response 4 in this:
http://www.computing.net/hardware/w...
"I do check the voltages in the BIOS from time to time and all voltages 12V, 5V and 3.3V are all generally just *below* 12, 5 and 3.3."
Any actual reading within 5 to 10% of the nominal reading is within a normal range and is probably okay.

Remove the AC power to your case and unplug and plug back in all connections to the mboard.
I've had one PS that was picky about how the wires connected to the main connector were positioned relative to the connector - if the wire bundle was sharply angled where it entered the connector, the PS would not boot the computer sometimes - if I made the wire bundle near the connector less bent, it booted every time.
Make sure all the individual wire metal ends are locked into the connectors, especially in the main connector - they should not move out of position in the connector while being plugged in.
......

Thanks a lot for your responses.

I did clean the entire PC including RAM slots and Im sure using the correct RAM. Also I did check the connectors on the PS wires. They seem to be in place. And back here I am getting PSs at US$ 10 for one with a 1 year warranty, about US $15 with a three year warranty while the *best* quality one can cost anything from $150 to $250.

And the RAM has been provided by my computer supplier who installed the new MB so I think there is a small chance of it being incorrect. Plus it worked well for about 8 months before it conked. I suspect the main reason for all the issues is the PS.

"" What I really cant understand is the intermittent times when the computer does start up."
"...there were issues starting it up once it was shut down and left off for a while. ""

"You didn't mention that before."

Oops - I re-read your first post. I sure got that wrong.

What jam was referring to:
"A system won't boot without RAM, but you *should* have gotten a constant beep code indicating that no RAM is present."

Make sure you have a speaker or speakers connected to the mboard so you can hear mboard beeps (see your mboard manual).
Remove the AC power to the case/power supply.
Remove all the ram.
Restore AC power.
Try to boot.
If nothing else is wrong, you will hear a pattern of beeps that indicate no ram is installed, or a ram problem.
E.g. for an Award bios or a bios based on one, that's often a beep of about a half second, silence for a half second, a beep of about a half second, silence for a half second, continuously.

Try that with the other PS connected.
((The other PS must have the same wiring colors at the same positions in the main connector (most do), although whether there is a white wire at position 18 or not (the only white wire) doesn't matter. If the wiring is different other than that, plugging it in and booting the computer has fried the mboard.))
If you still get no beeps you've got a major problem.

If you do get beeps, if cleaning the ram module contacts doesn't help get the computer to boot normally, you've got some other major problem. You could try one module at a time, or a third PS, but I doubt that will help.

<<<Update>>>
Well I am using my old PS. And my comp is running ok. The hitch is that it has been on for about 48 hours with occasional restarts. And Tubes I do have a system/MB speaker connected and it is working. I know this because whenever my comp boots up I get the one short beep and also I remember the longer beeps when my old RAM conked. So thats definetelt not the issue. The peoblem is major but I can't seem to find it.

Cheers!!!

Sometimes a hardware problem can cause the computer to reboot for no reason, but if it isn't that, it's a software problem in Windows. E.g. A friend had a rebooting for no reason problem (it black screened before rebooting) - it turned out it was a badly written anti-virus update that caused the problem.

Now that your system is relatively stable, try this:

Win XP is set by default to automatically reboot when it encounters an unrecoverable error.

To have XP possibly display an error message you can investigate instead of the computer rebooting:

1. Click Start, and then right-click My Computer.
2. Click Properties.
3. Click the Advanced tab, and then click Settings under Startup and Recovery.
4. Under System failure, click to clear the Automatically restart check box.
5. Click OK, and then click OK.

If you then get an error message, look at all of it's details.