I was using my computer - several apps open at once, but nothing out of the ordinary.
Then, the computer froze up (no Ctrl-Alt-Del response). I turned it off. On again... nothing.
When I turn it on, the HD activity light just stays a solid red for about 5 seconds.
No beeps. No sounds indicating it's booting.
All the fans power up, the optical drives do their usual test-spin.
Nothing comes on the display - not even the initial system details.
Dusted it out - all fans and power supply.
Opened and checked the power supply.
Tried with power only to the motherboard (unplugged drives and fans).
Removed the CMOS battery for about an hour.
Checked the CMOS battery voltage (3v - just fine)
Double-checked all connections.
Reseated the video card.
Looked for burst capacitors.
Everything seems to be getting sufficient power. The LED on the motherboard is the same colour it usually is.
This is not a newly built PC. It has been a normally-functioning machine for a long time now. I am baffled by this, and my best guess is that I need a new motherboard and/or processor. Help?