About a year ago we purchased the 2007 office ultimate for college students without buying the cds but we did burn a backup cd. I recently had to redo my computer & tried to use the cd but something was wrong with it. I dont know what I did wrong in burning it but it wont work, I tried it in another computer to make sure. So, I do have a valid key as we did buy the software but I cant find out how to reinstall the 2007 office ultimate. Any advice?