Little history. I have two 500 Gig hard drives (no raid). The first (disk 0)i used for XP and it was my main OS. The 2nd drive (disk 1) i used for test Win7 Beta. Well i finally got a good copy of Win 7, reformatted disk 1 and loaded Windows 7 Home Preimum. I want to use that as my main drive but when i try to format disk 0 (xp drive) it wont let me know. When i pull up Computer Managment and check the drives i see this (sorry no screenshots) pulled from Windows 7 OS: Disk 0 Basic: Healthy (System, Active, Primary partition) Disk 1 Basic: Healthy (boot,page file, dump,Active, Primary partition) I'm assuming I cant format Disk 0 because its the system but I have Windows 7 installed to Disk 1, not 0. And just for laughs, i disabled Disk 0 last night and the computer wouldnt boot up with only Disk 1 "active". I knew how to fix it so Disk 0 is "active" again and i'm able to boot up again. But, i still cant understand how i'm able to Load Win7 OS into Disk 1 but it not show as the main system. Any idea's on how to fix this would be great! Thanks !! Carlos PS. The reason i'm wanting to wipe Disk 0 is to test other OS's with a clean disk.