Usually when that happens you have some defective hardware.
In your case, my first thought would be your RAM is bad, and to use memtest86+ to test each module individually. If the whole unit is restarting however, that may point to a heat issue.
So, probably the first thing to try, since it's quick and easy, is to just remove the side cover on the computer and see if that improves anything. If not, get a copy of memtest86+, pull all but one memory module, then run memtest86+ though at least a couple of loops. Even a single error is too many for RAM, and be sure to test each module individually. Keep going even if you find a bad one, you may have more than one bad module.
If you do find more than one bad module, then it would be worth the time and effort to test each memory bank on the motherboard with those bad modules. If they still test as bad, then put in one that tested good before and make sure it still tests as good. You want to make sure what you have is actually bad RAM, not a bad motherboard.
Hello, I have an AMD Phenom II 955 cpu, a 1gb ATI Radeon 5770 gpu, Windows7 64bit, and 4gb of ram in my pc. I don't know very much about computers, but from what I can tell, this setup should be more than enough to run Starcraft II with ease. Yet roughly 85% of the matches I play end up with a crash. Most of the time the game itself just shuts down and I'm prompted to tell Blizzard what I was doing when the crash occurred, and sometimes my whole system will restart. I cannot figure out what is wrong here, my drivers are up to date, and I even play the game on the lowest possible graphics settings. Is there something I'm missing? Any help would be appreciated