|Your monitor is not receiving a video signal from the mboard. |
When you get no video, assuming you have the monitor plugged into a port it can get video from, there is usually nothing wrong with the monitor, and often there's nothing wrong your video adapter either - it's usually something else that is wrong.
Hard drives that worked fine before don't fail after the computer has sat unused for a long time, but sometimes mboards or power supplies do .
I am assuming you DID NOT change which ram you have installed since the computer last worked properly.
If you DID change which ram you have installed, see BELOW.
Open up your case and 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:
What to look for, mboard symptoms, example pictures:
Home page that site
- what the problem is caused by
- he says there are STILL bad capacitors on more recent mboards.
Pictures of blown capacitors, other components, power supplies, Athlon cpu's, etc.:
If there's nothing you can find visibly wrong with the appearance of your mboard capacitors and otherwise........
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:
If that doesn't help, then the most likely thing is your power supply has failed. This is probably the most common reason a system won't boot. Sometimes that's caused by the same bad capacitor problem inside the power supply, but there are many reasons a power supply could fail.
Some el-cheapo brands are well known to be more likely to fail - e.g. BESTEC, which are used on many emachines computers, and on cheaper models of other brand name computers.
NOTE that if you heard any unusual noise from the power supply when you first booted the computer or shortly after, such as a hissing or poping sound, or if you noticed any smoke or smell of something burnt, the power supply probably DID fail when you booted, and the mboard MAY be fried because of that event.
E.g. I had a Startech AT power supply do that to me recently, despite the fact it wasn't all that old - it hissed, smoked, and fried the mboard a few seconds after the mboard successfully booted (it beeped once like it should have, but will never do that again) .
Failing power supplies are common and can cause your symptoms.
Check your PS.
They often partially work, fans and hard drives may spin, leds may come on, yet you may get no video and the mboard will not boot all the way.
See response 4 in this:
If it is failing, you can usually replace it with any decent standard sized standard ATX PS with the same capacity or greater.
NOTE that sometimes a power supply fries the mboard while failing, and in that case a new power supply will NOT get the system working normally again. If you can borrow a known working PS with enough capacity, try connecting that BEFORE you buy a new power supply.
Standard (PS/2) power supply size - 86mm high, 150mm wide, 140mm deep, or 3 3/8" h x 5 7/8" w x 5 1/2" d , or very close to that, though the depth can be more or less for some PSs.
Don't buy an el-cheapo PS.
See response 3 in this:
Usually when a power supply fries a mboard, all or most of the components are still okay - the hard drives, ram, cards in slots, cpu are usually not damaged, however sometimes the floppy and optical drives, and much less often cards in slots, and least likely the cpu is/are damaged.
Ram that works in another mboard , or any ram you buy or have lying around, may not work properly, or sometimes, not at all - even if it physically fits and is the right overall type (e.g. SDram, DDR, DDR2, etc.; PCxxxx, xxx mhz) for your mboard. In the worst cases of incompatibilty your mboard WILL NOT BOOT all the way with it installed, and the mboard may not even beep - the ram has to be compatible with the mboard's main chipset, or in the case of recent mboards, compatible with the memory controller built into the cpu.
If you still have the ram that was installed when the system worked fine, try installing just that ram.
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:
Correction to that:
Once you know which module ID strings work in your mboard, you can get them from anywhere you like that has ram with those ID strings.
If you have brand name ram, it is usually easy to look up whether it's ID string is in a list of compatible modules found by using your mboard or brand name system model number.
If the ram is generic, that may be difficult or impossible.
It is easy to test for incompatible ram that has caused your mboard to fail to boot.
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.
Contrary to popular belief, it is extremely RARE for ram that worked fine in the same mboard to go BAD spontaneously, and even if it did, it is more rare for more than one module to be BADat anyone time. It certainly doesn't go BAD when the computer has merely sat unused for along time.
When you have a problem with ram that worked fine previously in the same mboard, it's almost always because the ram has developed a poor connection or is not all the way down in it's slot.
If you have changed which ram you have installed, if you have a problem with the ram, it's almost always because the ram is not comptible using it in the mboard.
If you do a ram test, do that AFTER having tried cleaning the contacts and making sure the ram is seated properly - otherwise any errors found may be FALSE.
If the ram is incompatible with the chipset, or on more recent computers, incompatible with the memory controller built into the cpu, it will likely FAIL a ram test - that is NOT a true indication of the ram being faulty - there is probably nothing wrong with it, and it will pass the test if installed in a mboard it is compatible with.
If a ram test DOES find errors, if you have more than one module installed, try the test with one module at a time - sometimes they won't work properly when more than one is installed, but it will pass when by itself.
If you want to try a memory diagnostic utility that takes a lot less time to run a full pass than memtest86 does, this one is pretty good - Microsoft's
Windows Memory Diagnostic:
It can be toggled (press T) to do a standard or a more comprehensive set of tests - use the default 6 test one first - if it passes one pass of that, use the latter one. A few of the tests in the latter set are intentionally slower.
If you don't have a floppy drive, see the Quick Start Information at that Microsoft link for how to make a bootable CD of the Windows Memory Diagnostic (you need Windiag.iso - you don't necessarily need to use the program they mention to add it to the CD).