Right-click My Computer, and then click Properties.
Click the Advanced tab.
Under Startup and Recovery, click Settings to open the Startup and Recovery dialog box.
Clear the Automatically restart check box, and click OK the necessary number of times.
Restart your computer for the settings to take effect.
You need to follow those steps and then your computer won't automatically restart. Then the next time it blue screens either the write the important info down that this page shows you:
or take a picture of the screen and post it.
The blue screen data is vital in figuring out why it's crashing.