Disabled Number Of Prosessers / Can't Run Computer

Alright, so i changed my number of processers to 1 to be able to run scarface the world is yours, so i saw some lags in my computer and ignored it, today i thought it was it, i tried to change it to two, i couldn't see it, i tried googling this or something, first thing i saw was something like "disable the number of procssers box" i disabled it, restarted my computer and I CAN'T RUN IT?!! i get 2 options, 1- start up fix and 2 start windows normally, i clicked normally first, didn't work, clicked startup fix, started somethings up and now it cant, it says i need to insert some CD/DVD or something, AND I DON'T HAVE IT!! i click start windows normally and it would just crash, give you that blue screen or whatever,