computer messed up after crash(blue screen)

so here's the thing, my computer froze then went to blue screen,it shut down automatically, next start up after welcome screen it says "preparing your desktop" and then blue-screen again. This happens a few times. i waited about half an hour before i could open my computer. After that i start up and manage to log on.
first thing i notice is that my start menu went completely empty except for all programs and my computer runs a program winch is "personalizing settings for:" and most of my Microsoft programs(media player, internet explorer, etc.) scroll by. And thats where i am now.

here is a list of problems i'm having:
start menu blank(except for >all programs)
some programs act like i started them for the first time (for example. I had to go trough Drop-boxes first time set-up)
All but the default file associations are gone
cant choose default programs, because when i select it it doesn't show up in the list

can any one please help me on this is there anyone who has the same problem i you do please reply as soon as possible thanks.