When i am playing games like WoW or Civ 4 my computer shuts off. It shuts off after no more than a half hour of use. This has happened to me 4 times in a row tonight. I had the computer off all day. I turned it on this evening and after a half hour it just turns off. The computer is about 3 months old. I am very frustrated.
I know that in the iMac G5's, if the internal temp got above a certain point, the computer would shut down on it's own to save the hardware inside. I don't know about the intel iMacs, but I have a sneaking suspicion that the temperature might be getting a little on the warm side. Download iStat nano here:
nonplussed,
First, have you re-installed your RAM, as it might have worked loose?
There's no need to actually remove the RAM for that, just use the ejectors/locking arms to loosen it, then push it back in all the way followed by locking in place with the arms. Don't depend on the locking arms to force it into position, as getting it fully seated should be done manually. The locking arms only hold it in place once it's seated.
You haven't listed your RAM, did it come with one module or two? If only one, you possibly need more RAM for those games. If you added third party RAM, it's possible that you have a faulty module.
edit-
As Trevor suggested, heat could be building up - and that could be due to overworking the hard drive if RAM is either faulty or insufficient.
Thanks yeah i was thinking it was the temperature. But i hadn't been running the computer too long. I got 1 512 mb ram that came with the computer and bought a new 3rd party 512 chip and installed that as well. Hopefully the ram isn't faulty i will try re-installing it thank you.
Check System Profiler's "Diagnostics" to see if there's any mention of a RAM problem found in the "Power On Self-Test" or found during a run of the Apple Hardware Test, which can be found on the Install Disc 1.
It doesn't matter how long you've been running the computer, the heat can build up fast. On my iMac, I can shut my computer down overnight, boot it up in the morning, and the temp on the CPU will be around 114 degrees F. However, if I start to do anything intensive like rendering video or playing a game full screen the temp reaches the point where the fans have to kick in high gear w/in about 5 minutes. So 30 minutes is plenty of time to get the heat built up. Besides, I think that the new C2D's are supposed to run cooler, so that means that the temp limit will be reached faster.
Also, like myhighway suggested, the RAM might be insufficient enough to do graphics-intensive tasks or other RAM utilizing tasks. When I got my iMac, it had 512 MB of RAM. That barely cut it for rendering video. Even with 512, it took over 2 hours to render just an hour of video. After that I got another 512 stick from Apple, and the rendering is real-time now. Also like myhighway suggested, the 3rd party RAM you put in there could be faulty, leaving your computer with just 512 MB of usefull RAM.