There is a problem with my computer so I want to delete everything off of my hard drive and reinstall windows 7. I contacted microsoft and talked to them about if my windows activation code would work and they said yes. I already have the iso for windows 7 on a usb flash drive but I am still curious about deleting everything off of my hard drive. If I deleted everything off of it would windows 7 install correctly. What would be the best program to use to delete all of my files. And would the hard drive still be usable if I deleted everything off of it?