When your PC is booting up, Press F8 a few times, choose "Don't automatically restart on system failure". Induce the failure again, this time you presumably will be confronted with a blue screen, record the data on the screen and google for the error message number, will look something like this "0x00000009c" or something.
Will most likely be a problem with Video drivers.
Good Luck. Post the Error message here maybe we can help.