OK so I had windows vista and i had a corrupt file. I installed the vista service pack 2, and this screwed everything up so that I could not boot up vista anymore. My school sells window 7 for $50 so i thought it would be a good time to do the upgrade. I put the disc in booted up and am now running windows 7. However, my hard drive says that there are 150/220 GB occupied, with only 70 GB filled. What do i need to do to clear everything off my hard drive so that all that is on my CPU is windows 7? My disc says Windows Ultimate 7 32Bit english disk kit Thanks!