I believe I have a unique video problem. My monitor will be fine when I boot system into Windows xp Pro. After about 5 to 10 minutes it will black out and not come back on. If I re-boot the system it is fine again for a short time and then back off.
I have done the following and have run out of ideas.
1-Power supply voltage within limits.
2-AC input power is not low.
3-Have tried three monitors, all the same problem.
4-Have installed new video card with updated drivers.
5-System and CPU temp well within limits.
6-Have eliminated the surge protector.
7-Have moved entire system to another room.

Now the strange part:

When I take the system to the computer shop it never fails. It will run with any of my or their monitors and does not falter at all. This was the reason I checked the line power at the wall.
I have not tried a new keyboard or mouse as yet.

System Spec
Win XP Pro SP 2 and up to date
512 Megs SDRAM
3 cd rom drives
Running AVG Antivirus
MS Antispyware
Adaware SE

Any suggestions would be appreciated.
Bruce

wow this is a real headscratcher... 3 montors AND a new vid card... then it works fine when u take it to a tech shop? i'm clueless...

i went to a service call just last week, a brand spanking computer 2 days old, after exhausting all hardware/ups,power/software/cords issues, we gave him another brand new computer. same issues as you, and it still harped him. we have had his computer to our shop, both new ones, numerous times, no issues at our shop. the other variable, LAN/Internet, we called the ISP, Rogers in our case, got them to replace their cable modem, now perfect.
this may not be your issue, but i thought id share my recent experience with the "unknown" with you as it was as strange as your issue. try taking off ethernet cable , just for fun.
good luck