ok so ive build my computer fine and i have a previous OS installed on the hard drive. I was wondering is there a way to install a clean copy of windows 7 with out the cd rom. I do not have the cd rom yet. I have the windows 7 upgrade cd key and i have the files, I can run it but it doesnt say a clean install it says that the old files will be put into a folder called old. I want a fresh install and everything deleted that is old. Curiosu how i can do this?