Another no BIOS/no beeping PC

[rvashko]

PC powered down last night after 4 hours of inactivity, as it usually does.

Went to start it up this morning. Case fans spin up, as does processor fan. Hard drive spins up. HDD LED is solid red.

Absolutely no BIOS/POST/Start-up text on screen, and no error beeps. Completely blank and silent.
No access/reading sounds coming from drive.
No power getting to keyboard, mouse or CD/DVD drives.

Removed video card and rebooted - no change, no beeps (i.e., no error beep for no video adapter detected), no text on-screen.
Removed and reseated CMOS battery. No change.
Reseated video card and all cables and RAM. No change.

PC is a kit I built about 3.5 years ago. I was worried it might be a bad HDD, but even if it was, I should still get some sounds or text on-screen, no? Same thing for a bad video card - I should be getting some visual or audio cue that something was wrong, shouldn't I?

No funky smells. Visually, nothing appears to be wrong when I crack open the case.

I've looked through other threads, and a lot of folks have suggested a new power supply. I just don't understand why a faulty PS would feed power to all fans and the HDD, but prevent the BIOS/POST from starting.

I hate buying stuff (like a new PS or HDD) when I'm not sure it'll solve the problem, and when it doesn't, I then have to return a perfectly good item back to the store.

So any suggestions would be appreciated.

Thanks,

rvashko

[comlor]

You don't have to get a new power supply to test if it is bad. You can test you PSU with a voltage meter to see if there is a problem.

The following if from the following URL:
http://www.lockergnome.com/it/2005/03/02/learn-how-to-diagnose-power-supply-problems/

Checking The Power Supply
If the wall outlet and the power cord are good, make sure the connection at the motherboard is secure. Then you may have to face the fact that the power supply itself is bad. If you have a multimeter, you can test the power supply output before purchasing a new one. Simply follow these steps:

Turn off the PC, but do not unplug it. Open the system unit. Set the multimeter to read DC volts in the next range higher than 12 volts. Locate a power connector similar to the hard drive (or CD-ROM drive connector that is unused) and turn on the PC.
You can also unplug a drive connector and use it. Turn on the PC and insert the BLACK probe into the power connector on one of the BLACK wires. Touch the RED probe to the YELLOW wire on the power connector.
The multimeter reading should be +12 volts. Now touch the RED probe to the RED wire and the reading should be +5 volts. If no readings or different readings occurred, you’ll have to replace the power supply. If the readings were correct, you should check the P8 or P9 connectors at the motherboard. These connectors may also be named P4 and P5. To check these connectors, perform the following:
Insert the BLACK probe into P8 at one of the BLACK wires. Insert the RED probe into the P8 connector at the RED wire. The reading on the multimeter should be +5 volts.
Check the power going to the motherboard connections by inserting the RED probe into P8 at the YELLOW wire and you should get +12 volts. Leave the BLACK wire touching the BLACK wire at the P8 connector. Check the BLUE wire and the reading should be a -12 volts.
Now move the BLACK probe to the BLACK wire on the P9 connector. Test the WHITE wire by inserting the RED probe and the reading should be -5 volts. Check the RED wires on the P9 connector and you should get +5 volts on each red wire. You won’t get exactly 5 or 12 volts, but the readings will be very close, such as 5.02 volts.
If the Power Supply is a couple of volts off in either direction, such as when the RED wire should be reading -5 volts but it reads -8 volts, or if there are no readings, replace the power supply.
DO NOT remove the power supply from the system unit case when performing these tests. DO NOT perform these tests if you do not feel comfortable. Be sure to remove any and all electrical static build-up from your clothes and body BEFORE touching any parts inside the system unit. And NEVER open the power supply case for any reason, since high voltage may be present.

[OlyComputers]

Could be a bad PSU, but I'd guess a failed motherboard, that's usually the case when a previously working (IE: properly configured) system just stops posting out of the blue.