My screen blinks and then my system reboots itself like someone pushed the reset button.

This sounds as if you are encountering a Blue Screen error but your system is configured to reset on errors such as these. You can prevent the system from automatically restarting on error by following these steps:

1. Hold down the Windows key and press the Pause/Break key (this opens your System Properties)
2. Click on Advanced System Settings (in XP, click on the Advanced tab)
3. Under the section labeled Startup and Recovery, click the Settings button
4. Under the section labeled System failure, uncheck the box labeled Automatically restart
5. Click Ok and OK and restart your system for changes to take effect
6. Having made this change, if your system encounters a Blue Screen error, it will remain on the screen until you restart the system yourself via the power button. This often provides you with information helpful to determining the cause of the error, specifically the error name appears in ALL_CAPS_SEPARATED_BY_UNDERSCORES or a particular file is mentioned by name (normally a file ending in .EXE, .SYS, or .DLL) as having cause the error.