You may be able to partition the drive, keeping the data on the D partition and doing a clean install of windows on the C partition. Does the HDD already have Windows installed on if from your old Computer? I think you will be much better off to take the time to figure out what data you want to keep, copy it off to another drive/computer, and then do a clean install of windows. Even if you partition the drive, I "think" you will still have to re-install all of your programs after a Windows install, unless you are good at editing registry entries.