your pc is probably infected, then again it could be the HD.
you also have just said the equivalent of calling a Doctor on the phone and saying " I am sick, what do you think is wrong?"
The BSOD has an error code that can be most helpfull in determning what is wrong with your pc, if you post the error code we will have a look, if the error code just flashes by
and the pc reboots
click advanced tab
then down at the bottom
click settings for start up recovery
uncheck automatically reboot