Whats wrong with my comp, and how can i fix it?

every time i start my computer a blue screen pops up to do a file variation... problem is ALL files are unreadable and it always stops 38% through step 2. and I cant download my msn (which i unintalled because befor it would try downloading something for msn every time i start my comp.) now i dont have access to the dictionary. Its been like this for like 2 weeks now. HELP ME!