Argh - No video on power on (No beeps no bios screen)

[Citadel535]

My pc was running fine for over a year with a FX 5600 in it. I booted it one day and found the monitor was staying in sleep mode and the BIOS screen wasn't even coming up. I checked the card/cables and still had no luck. I put in the original system's Geforce 4 mx and it ran fine and I decided the card must have failed and got a new one to replace it anyway. I put a new 6600 card in, ran for around a month with no problems. Then it did the same thing the other card did, boot pc, no bios loading, monitor thinks it is in sleep. I tried attaching a different monitor but still the problem continued. I removed everything from the system and tried booting with one of the two new cards and had no luck.

So now I am sol as the return period for the new card is gone. I even bought a brand new 500w PSU thinking it wasn't getting enough juice to the cards. My question is why does the PC run fine with the Geforce 4 mx and not with the 5600 and 6600 (both different brands btw).

What should I do? My pc is still under warranty but the original card works fine but not the new ones. I don't overclock my components so I don't think it is heat related.

Help! I need my gaming fix

 

[Zepper]

Boilerplate-01:
. Common causes of failure to boot (no video, no beeps) assuming PSU isn't totally dead (or set to the wrong voltage):
1- RAM, CPU and/or AGP video card not seated properly, a bent pin or corrosion.
2- Drive data cable on upside down or only on half the pins or shifted a pin or two (usually Floppy or Zip drives).
3- CMOS needs to be cleared (AC power must usually be disconnected or attempts to clear CMOS may fail) Unless your mobo does not use a power-off CMOS clear - check your mobo manual for specific info.
4- On some new mobos there is a CPU protection feature (esp. on Asus/Asrock Athlon/Socket A mobos) that will not allow the system to start if there is no fan (or a fan without a working speed sensor wire) connected to the fan power connector on the mobo (specifically marked "CPU Fan"). If you tried to start your machine without a fan properly connected, you have to attach a proper and working fan and clear the CMOS before it will boot.
.bh.