about 2 months ago i built a pc. everything works on it like internet, networking, applications but whenever i try and play a game for some reason it will only play for 10 minutes or so and then the game shuts itself off and it returns me to the desktop.

i checked the error logs and the information i was given was as follows for every time a game crashes:
The description for Event ID ( 0 ) in Source ( ) cannot be found. The local computer may not have the necessary registry information or message DLL files to display messages from a remote computer. You may be able to use the /AUXSOURCE= flag to retrieve this description; see Help and Support for details. The following information is part of the event: 7.

i have fitted my pc with extra fans to make sure it isnt a heat problem that is causing this, the highest the CPU gets is 90 degrees C. i have also tried downlaoding drivers for the graphics card but i cant be sure they were the right ones. any help will be greaty appreciated as i built the pc to play games and that is exactly what it wont do!

Could it be the screensaver? Default is 10 mins? Failing that try and get another graphics card to try as the one your using may be faulty. Also try some different ram. Process of elimination unfortunately. Switch off power managment as well.

"Unknown has caused an error in unknown, unknown needs to restart"

i agree with scott29, it sounds like you have a screensaver or power management that is still running. we wait for your feedback.

I have exactly the same problem, except the timing is not consistent. Sometimes the game runs for 10 minutes, sometimes for an hour. The PC is also a custom-build for gaming. NVidia GEForce 03 w/ 128MB video RAM and a P4 processor at 3.06 GHz w/ 512 MB RAM running WinXP Pro. Games are specced down to teh lowest level (800x600, etc) and still these damn crashes - no sscreensaver or power management enabled.

Please help before I throw the machine out of the window.

What games are you playing? Some companies, for example, have a "relationship" with nVidia and apparently those cards tend to play better with their games (you can usually tell if they if there is a "relationship" by looking on the box of the game). It could also be video card drivers that aren't sitting right with your computer. Oh and by the way, 90 degrees C is equal to 194 degrees F. Your CPU could probly take a lot more abuse but in some BIOS there is a setting that will make your computer "chill out" if the temperature gets to high.

Might want to look into those possibilities.