Recently I got a All-In-Wonder 9800 Pro video card and all the games(Warcraft III Frozen Throne, Age of Mythology, Thief 3) I play work for about 30 minutes to an hour and then the computer justs reboots. Have no idea what the problem could be.

i had the same problem when i'd try to start a game it'd reboot my computer. what happened is i forgot to take out the old graphics card before installing the new one so they'd conflict and cause an error to reboot. hope this helps