I wanted to re-install Windows 7 on my computer. I started the installation process thinking it would prompt me to format my hard drive (and getting rid of the old Windows installation) at some point, but that never happened. Instead, the installation froze at some point, forcing me to abort it, and afterwards, it was unable to continue.
So, I installed Ubuntu and formatted the hard drive, thinking I could just install Windows again. Both Windows 7 and Windows XP told me it was impossible because the hard drive was not formatted in NTFS, and I have no idea what that means. Most online forums aren't helpful, I've only found one answer which I am considering trying out now.
Yax is right. So.... do you have any friends with a Win7 computer? I know this sounds like a pain, but if you pull the hard drive, and stick it into someone else's computer as a secondary drive, then use the Window's formatting option, that works ok.
I'll try to look this weekend on how to use the Windows live disk to reformat the pc-- it may be 8 or 10 hours til I can get to that point, but if I can I'll post you some other options.
http://www.sevenforums.com/installation-setup/91611-trying-install-windows-7-over-ubuntu.html
Look at that link- someone posts some commands about 3 posts down, that may help you??