I see this post is ...about a month old and was wondering if you eventually got this sorted?
Idk if you can even get winXP booted, but if you can I use this nifty partition tool where you can work on it in a windows environment.
I know there are lots of different ones out there and this info may seem infantile to some members. However it worked for me and it's FREE!
there is also a bootable partition manager (also FREE) if you can't get it to BOOT...
Just be careful what you do with it. READ & Understand everything before using it.
It could wipe out everything if your not careful executing commands.
Wouldn't want to send you down a BAD Path.