I broke my computer, and want to fix it?

I upgraded my computer (desktop) from vista to windows 7, my stupid self did it through a virtualdvd thingy, so when i restarted to computer to get windows 7, it kinda broke and now says "Boot from CD" and ive tried getting new Windows 7 Recovery disks and that wont even work because when i put them in it says that i dont have to correct file or some sort like that..... I want to know how i can completely empty my computer and start from vista, or windows 7(doesnt matter but idk how to get the vista file to do this) i have some new windows 7 recovery disks but i dont know how to do this yet..... If anyone can send me to a guide on how to completely empty my computer and use a recovery disk to start from scratch that would be great.