My guess would be that it's shutting off, not going into sleep mode. And since this seems to happen after playing a game, it tends to point the finger at heat buildup being the cause. Something in the computer reached a critical temp which triggered a failsafe causing the computer to shut off before permanent damage happens.
So when's the last time you blew out the dust bunnies from the fans? It's something you should be doing roughly every 6 months. If there's a fan in the system, it should get a nice blast or two of compressed air to dislodge any dust bunnies that may have collected.
My computer goes into sleep mode when i was playing game and cant wake up when i used kekboard or mouse. After i restart com same thing happen again after i use the com for less then 5mins. I check the setting for sleep mode but its not on. Some times after i on the com, after login account it goes into sleep mode without letting me do anything. anyone knows how i can stop this promble?
Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic