Hi, I have a computer with Vista Ultimate OS. I have 3 Hard drives in it. The first is for the OS. The other 2 are 500GB drives used for file storage. Yesterday, when I turned on the computer, I got a disk boot error. After some research, I determined that I needed to get a new hard drive and reinstall the OS. I could not find my Vista disk so installed a MSDN version of XP. I then had to select windows update to get the XP OS up to Service Pack 3. When I plugged my 2 additional hard drives back into my computer, the hard drives show up, but when I click on them, I get a message stating that I need to format the disk. I have gigabytes of photos, videos, etc. on these drives and can't format them. I'm wondering why I can't see my files and is there a way to fix this? Is this because they were used on Vista orginally and now are hooked into an XP OS? Thank you very much for your help! UPDATE: I've determined that when my hard drive with my OS on it crashed, it caused my other 2 drives to convert from an NTFS file system to RAW. So Vista interprets these drives as empty and in need of a format. The question is: How do I get these drives back to NTFS without formatting the disks? I have all of my info on there and cannot format. I've tried taking the drive and putting it in an external casing, thus hooking it up via USB. This does not work. Vista still thinks the disk is empty and needs to be formatted. It's also been suggested that I hook the drives (via external case) to a Linux system. Supposedly LInux can view contents on a disk that are in a RAW format. I'll keep you posted. If anyone has additional suggestions, please reply!