Have you tried uninstalling and re-installing PSP7, hippie54?
If you are using XP, right-click on "My Computer", choose Properties > Advanced tab, click the "Settings" button in the "Startup and Recovery" section, and in the "System Failure" section, untick the "Automatically Restart" option. Click OK, Apply and OK to exit. Now try to replicate the problem that caused the PC to shutdown. This time, instead of shutting down, it should display an error message. Post that error message.