Alltaken’s advice is right, except the Windows “recovery console” is not always available by default (via a menu during bootup), but AFAIK you can get into it by booting from your WinXP install disk (there’s an option to recover vs install). Once you get in that way, use the fixmbr command like Alltaken said. Type “help” at the command prompt in recovery console to get a list of available commands. Use “help [command]” to get specific info on the various commands (replace “[command]” with the name of the one you want to know more about, of course…)
I would highly recommend taking lightning’s (and my earlier) advice and just leave your “C:” partition as is (don’t resize it) and make a “D:” partition in the available space of your drive (after deleting the *nix partition(s))
I would then move your “My Documents” folder to that D: partition. Simply right-click on the “My Documents” icon on your desktop, select “Properties”, select the “Move…” button, select your D: partition, click “New Folder” and type “My Documents” in the box. Okay out of everything - allow your documents to be moved to the new location - and you’ve successfully circumvented Microsoft’s insane use of the “C:\Documents and Settings” folder tree to store all of your data.
All this to say, its very wise to keep all of your data separate from all of your OS and Program files. True, its even better to keep them on a separate physical HDD, but a separate partition is a step in the right direction. The reason: in the event of a system failure, your data is the only thing that cannot be reinstalled from original media (or downloadable installation packages)! Keeping it all on a separate drive or partition allows for much simpler backup of what is most important: your data. (It also helps keep defragmentation-related performance issues to a minimum, but that’s a whole other discussion there…)
As to using a linux solution (the only free partition utilities out there, AFAIK) to resize an NTFS (read: Microsoft Proprietary) partition is dodgy at best and not recommended. I’ve done it myself in the past, but I would advise buying a Windows-specific solution (like Partition Magic or similar.)