I had the same problem. The "first" 5.0 final version had a bug that caused your system to crash when you tried to exit. A workaround was to kill the process with Procdump or any similar tool, instead of using the exit button. I guess you're using Windows 95/98/ME ? Afaik it was a problem that only happened on 9x systems.
After a few days "5.0 final B" was released, and this version fixed this bug. You can find it at pid.gamecopyworld.com
PID is not bad, but i prefer Aray scanner