If you have 2 that means that they are 256 meg's a piece, I recently had a bad stick of memory giving me that same problem. For example, your two sticks of memory, let's say stick A and stick B..Remove 1 stick of either, doesn't matter at this point. Then go back in and try and play again if it does the same thing, then go back and put in the other stick that will rule out the memory problem, if that doesn't fix it the other possiblity would be heat, if you have some kind of pc health thing that you can monitor from windows good.. If not, you will have to go into the BIOS and see what the temperature is on my P4 it stays at a temp of 43 degrees C. if it looks like it may be a little high, take the case off and try and run it again.