Hi , Can someone please advise on the best way to format a hard drive to change operating system without wiping an additional hard drive? I'll explain.. I recently purchased an old desk top which I have using. I want to change the operating system from XP to windows 7. There are 2 hard drives (I think). E: drive which has a total size of 9.75gb - 159mb free (of which the operating system and program files are) and Crive which has a total size of 1.80TB - 900gb free. Can I format the E: drive and change the operating system without wiping the data on drive C:? Any guidance will be greatly appreciated.