While in a middle of running a game, Neverwinter Nights (native Linux client), Ubuntu abruptly goes into standby mode in the middle of a game. When it returns from standby, I get a black screen and Jaunty notification that the wired network is disconnected (the notification doesn't disappear). The mouse pointer is frozen in the middle of a screen and I cannot move the mouse pointer so I'm forced to force shut down the machine by holding the power button and start it up again.
Could overheating be causing this? It's happened twice so far since I got a new ATI graphics card and started playing games on the machine. It seems to happen during battles, where lots of graphics are flying around. My machine is an older Dell Dimension with a Pentium 4 HT processor which have a reputation for running warm. Thanks for any suggestions on what to do about this.