The following post is long but thorough. 😉
My Viao went dead recently — crashed directly from XP Pro to a black screen with no messages beforehand. Attempts to power down, then back up were unsuccessful.
I opened the case and found the culprit: The heatsink over the motherboard’s video chip had lost its mooring and was hanging there, touching the video card. I successfully put it back in place, but can no longer boot up.
Thinking the video card had been damaged, I replace it. No go.
Pertinent facts:
* The green led on the motherboard is lit when the computer is connect to an AC source.
* The power supply seems to be working — at least the fan is running when the system is on.
* The blue power light on the front panel is lit when the system is on.
* When powered on, the keyboard’s caps lock and scroll lock keys don’t work, but the num lock light does turn on when the key is pressed.
* I don’t seem to be able to access the system’s shared resources via my home network.
Here are the tests I’ve performed so far:
* Boot with old video card: Powers up; front-panel hard disk access light flashes once on power-up, then stays off; nothing on monitor.
* Boot with new or no video card: Powers up; front-panel hard disk access light remains constantly on; nothing on monitor.
Also, the monitor works fine — I’m using it right now on another system.
I’m looking for any help determining which part or parts to replace. I have lots of experience at repair on a parts-replacement basis, but I have no diagnosis tools to find out what particular part(s) is failing.
Many thanks in advance!