i switched my old motherboard and processor out with new parts and didn't delete anything from my hard drive. I dont care if i loose anything i just want to start up the computer. i have whe windows disc and product key. My original thaught was to plug in an external hard drive in and install windows 7 on that, than when i was done i delete the info on the old hard drive and go back to using that but i just want to do this as simply as possible.