it depends on what the blue screen said
sometimes its a very simple fix of re-installing a device driver
to stop the blue screen flashing past
goto
control panel>
system>
advanced tab>
startup and recovery - settings>
under the title - system failure
untick - automatically restart
http://support.microsoft.com/default...b;en-us;320299
now when it crashes - it willnot restart and the blue screen should stay on the screen
post the info on the screen
it will give the errorcodes and a filename, if caused by a driver.