Computer powers up but won't post

March 8, 2009 at 03:07:40
Specs: Windows Vista
I handed down my older computer to my younger brother taking out and replacing only the PSU, hard drive, and DVD-rom drive with his own parts from his older computer. The previous configuration worked fine before I took out and replaced the HD, PSU, and DVD drive but now that I'm using the "new" (technically the only new part is the PSU but the hard drive and dvd drive worked fine in his other computer) parts, the computer won't boot. The CPU and case fans start, the DVD drive lights up and opens/closes, and I can hear the hard drive spinning but nothing displays on the monitor and the motherboard doesn't emit the standard post beep to indicate that it's working.

I've tried:

A new PSU that works fine on another PC

A new monitor (not that it matters since as I've said, I don't even get any post beeps)

Booting with only the CPU connected (I do actually get a beep when I do this)

Booting with one stick of RAM


Removing the CMOS battery for a few hours

The fact that a confirmed-working PSU still gives me the same problem leads me to believe that the other two parts can't be to blame, especially since from what I understand, a PC should at least boot to the BIOS screen or sound a beep if a hard drive is unplugged which doesn't happen.

I also can't imagine that the motherboard or RAM is to blame since as I said, they worked fine until I tried the new parts and I didn't even remove the motherboard or memory from the case.

Specs (all a little over a year old):
AMD Athlon 64 X2 5600+
MSI NX8500GT-TD256EH GeForce 8500 GT 256MB
G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM

See More: Computer powers up but wont post

Report •

March 8, 2009 at 09:34:19
Did you unplug the AC to the PS, or otherwise switch off the AC to the PS or the computer, AT ALL TIMES, when you were fiddling around inside the computer? If you didn't, you may have damaged something - ATX mboards are always powered in some places even when the computer is not running, as long as live AC is being supplied to the PS, the PS switch is on, and the PS is properly plugged into the mboard.

See response 2 in this - try cleaning the contacts on the ram modules, and making sure the modules are properly seated:

The mboard probably requires an extra power connection from the PS other than the main 20 or 24 pin connector, and the video card may require an extra power connection from the PS - did you remember to plug that/those in?

If you moved a jumper to clear the cmos, did you remember to move it back to the "normal" position?

The cpu fan must have either 3 or 4 wires, it must be connected to the 3 or 4 pin cpu fan header on the mboard, and it must be connected to the right pins. If that is wrong, usually the mboard boots anyway but the mboard shuts down in a few seconds when no cpu fan rpm is detected by the bios, but in theory it's possible the mboard may not boot at all when no cpu fan rpm is detected. Sometimes there is an alignment tab on the mboard header that is easily broken off or bent - if that is missing or bent, it may be possible to install the connector from the fan on the wrong pins or the wrong way. A 3 wire connector from the fan must be on specific pins on a 4 pin mboard header - see the mboard manual.

There may be a poor connection inside your case somewhere.

Unplug the case/power supply.
Power off your monitor.
Open up the case by removing the left panel as seen when you're looking at the front of the case.
Check all the connections of the wiring to make sure they are all the way onto their pins and into their sockets, especially the main connector from the power supply. The wires close to the mboard going into the main connector/socket should be more or less perpendicular to the mboard surface rather than at an angle. Make sure all cards in slots are all the way down in their slots.

While you're in there, if the cpu fan/heatsink has mung (dust, lint, etc.) on it, clean it off, but DO NOT use a vaccuum cleaner to do that (they produce a tremendous amount of static electricity when running, and anything connected to them can discharge that to your components ) - use canned air, or an air nozzle if you have access to an air compressor, or an artist's brush that can be used in small spaces, etc. If may be difficult to clean the top of the heatsink under the cpu fan - the most likely place to have mung on it - and the bottom side of the cpu fan blades unless you remove the fan. If you have a case fan, clean that too if it needs it.

The ram should work fine in any AM2 or AM2+ mboard, but
- if the ram you have installed is not the ram that was in it when the same mboard worked fine previously, we have heard of people having problems with G-Skil ram,
OR - the ram may have been damaged by something you did.
If your problem is caused by the ram not wanting to work in this mboard, or by the ram having been damaged, that is easy to check for.

Make sure you have a speaker or speakers or the equivalent connected to the mboard so you can hear mboard beeps (see your mboard manual if you need to).
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 get no video but 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.

Report •

March 8, 2009 at 10:40:02
What are the specs on the replacement PSU? That is probably the issue. Disconnect ALL the drives from the motherboard and try booting. If no go the PSU may not be up to the task.

Report •

March 8, 2009 at 14:00:53
"If no go the PSU may not be up to the task. "

The PS must have enough capacity to handle the system when the video card is connected. See the specs for the video card model on the manufacturer's web site. The minimum required wattage and often the minimum required amperage at 12v is stated somwhere in thespecs, often under system requirements.
If you don't find that, any card with the same video chipset has very similar minimum PS requirements.

If the PS does not meet or exceeed those specs, the computer may boot anyway but the PS will be damaged in a short time because it is being constantly overloaded, or the computer may not boot at all.

Report •

Related Solutions

March 8, 2009 at 15:32:17
The new PSU is admittedly a cheapo 420w Raidmax case PSU but like I said, I did try another power supply which works fine on another computer (it's a nice 500w Thermaltake PSU).

Further, whether or not the graphics card works is irrelevant because A: I tried using the VGA port on the motherboard with the no GPU plugged in and B: Like I said, the GPU worked fine before swapping the hard drive and DVD rom drive and C: Even if the GPU had a problem, I would think that I should still get a BIOS beep.

As for all of the other things mentioned... rest assured, I tried them all. I also can't stress enough that the PC worked fine minutes before changing the configuration with the new PSU/HD/DVD drive and I didn't even remove the motherboard from the case.

Finally, like I said in my original post, I've already tried booting with just the CPU plugged in and I do get long beeps which I would think would imply that the motherboard isn't shorted (at the same time however, I can't imagine that that would imply bad RAM since I've tried both sticks by themselves and I still get no beep and again, they worked fine before).

Report •

March 8, 2009 at 17:40:01
Then did you try re-seating everything?

Report •

March 9, 2009 at 00:56:40

I tried that

Report •

March 9, 2009 at 03:30:16
I would suggest pulling out the motherboard and bench testing it. If you didn't damage any parts by ESD (static) then it either has to be the graphics, PSU, connections or a case short.

Verify that the case standoffs are placed under each screw hole and ONLY under each screw hole.

Bench test by using ONLY the following. board, CPU/HS/fan, 1 stick RAM, keyboard and monitor to onboard video. Connect only the 24 pin connector and the auxillary power to CPU connector. No case wiring to motherboard. Momentarily short the two motherboard pins normally used to connect the power switch using a screwdriver.

Report •

March 9, 2009 at 08:06:48
"...I tried using the VGA port on the motherboard with the no GPU plugged in..."

"... tried booting with just the CPU plugged in and I do get long beeps..."

Assuming you don't have a metal mounting post in the wrong place, and there's nothing wrong with the PS or any connections to the mboard including that of the cpu fan, and the clear cmos jumper is in the"normal" position - it's extremely unlikely to be because of a cpu problem if you haven't touched that - then ........

This mboard has an Award bios.

In my experiences with many mboards with an Award bios a long beep indicates a video problem - that's what I have gotten when there is no graphics card plugged in or it's not all the way down in it's slot, for a mboard that has no onboard video.
According to that, you should NOT get a long beep when there is no graphics card installed, if there was a monitor plugged into the onboard video.
If you DO, the mboard is probably damaged.

When you have no ram installed and you do have a graphics card installed with a monitor plugged into it, or you don't but you have a monitor plugged into the onboard video, you should probably get the beep pattern I describe at the end of response 1. If you DON'T, the mboard is probably damaged.

Report •

Ask Question