About a week ago I encountered a very frustrating computer problem. When I try to play Fallout 3, the computer would shut down after a few minutes. This wasn't just a crash to desktop, freeze, or blue screen of death - the computer powered off suddenly. I thought perhaps I was having a heat problem, so I bought some canned air and blew all the dust out of the casing. That seemed to work for a while, but now I'm encountering the same problem when playing Left 4 Dead 2. The computer is less than a year old, and pretty high end - I shouldn't be having these problems.
All other applications work fine.
Google-fu pointed me to the overheating possibility, but now that the dust is gone and I've verified that the fan is working, I'm not sure what to do. Anyone have any ideas?