How to stop restart and see Blue Screen Error Code in windows 7

Hello friends,
I boughtthis computer last year and that is the first time today I got a blue screen.
As while I was working on my pc it flashed on the screen. The blue screen flashed so quickly that I was not able to see the error code.
I checked out the dump file and what I found that it was 475megs?! I also tried to open notepad as well as MS word and both the time answer from windows7 was " I dont have permission to open it" and I was logged as admin.
I dont know what wrong is going on with my computer.
Can anyone help out me what to do?