I am a bit short on detail but have had similar experiences. They are usually caused by recalcitrant "residues" from a previous installation. There is a command line you can use, but since you are planning to go back to Win, a "wiping" tool, which just fills the HD with zeros, would be better. A "Technician's Toolbox", or say "Rescue Disc ubcd411" would provide a choice of "wiping" tools.
I decided to try Ubuntu 8.04. My hard drive was so full that it wouldn't partition for Ubuntu. So I decided to just let Ubuntu take the hole computer. Now I would like to instead have a dual boot system. I pulled out the factory OEM disk to bring the computer back to it's original state. Unfortunately I am now getting an error that I believe is from having the Ubuntu OS on the computer. When I boot up the computer I am getting:
Grub Loading stage 1.5
Grub Loading, please wait......
I have tried using a rescue disk, removing the partition of the hard drive. Then once again using the factory OEM disk to bring to it's original Windows XP state. I'm still getting the same messages. Is there a way I can get my computer back or will it have to be solely an Ubuntu machine from now on?
I did go into the Bios but didn't see anything there that indicated that something had changed. Would appreciate help in getting my computer back.