I have been using the Windows backup function, and there's a lot I find puzzling. I'm running W7 Home Premium SP1. I have a 2TB HHD (C: drive) and a 2TB external drive for backups. I had no problems until I added some huge files to my drive, taking it to about 3/4 full. At that point the backups always failed - not enough space, apparently. So I deleted everything on the backup drive, and ran it again overnight. 8 hours later it was still running, so I cancelled the backup and removed some of the big files to a 3rd drive, leaving my C: drive just over half full. I emptied the backup drive again and ran the backup. This time I let it run overnight and over the next working day. It completed, but the size of the backup is more than the used portion of my C: drive by about 300GB. Why would this be? It didn't happen like that previously. Is it possible to do a backup only of the user data files (there are 3 users)? If I am having to restore from a backup it would probably be because I've re-installed the OS. Is there a step-by-step on how to restore to a clean installation? I can't seem to find one. Sorry for going on a bit. Any advice appreciated.