Sounds like Windows is crashing and automatically rebooting (the default behavior.) In order to diagnose this, we'll need to stop it from restarting.
On the black screen that comes up, have your friend choose the "Disable Automatic Restart on System Failure" option:
Then, the next time it fails, he'll get the infamous Blue Screen of Death. Have him write down the all the information that the BSOD shows (especially the part that looks like 0x000000(0x000000, 0x000000, 0x000000, 0x000000)
. This numeric code can tell us a lot about the specific problem that Windows is encountering and we can move forward with that info:
Edited by Amazing Andrew, 04 December 2009 - 03:15 AM.