In your advanced system settings (found through control panel) there are options relating to debugging & error msg's, by default Windows will reboot in the event of such an error.
What you need to do is disable this, so that when a crash happens you either get a error code on your desktop before it reboots or you get a BSOD after the reboot.
If you can get either of these messages to appear there will be details regarding the file or process that caused it along with an error code, this will be invaluable in try to solve this.
Good Luck
