The XP installer "will not" be able to remove Linux VFat12 partitions. One great tool for both creating and removing partitions for Windows and Linux alike is the Gnome Partition Editor. If you have a program for burning iso disk images onto bootable cd-rs the free tool can be downloaded from
http://sourceforge.net/projects/gparted/ A full definition is seen at
http://en.wikipedia.org/wiki/GParted
First you will need a program that can burn iso images to cd-rs if you have a cd writer available. BurnOn has a free to try-free to keep version found at
http://www.burnworld.com/burnoncddvd/
If and when you are able to burn GParted and boot from the disk you simply keep pressing the enter at every prompt until reaching the main program screen. Note at the right you will see a small tab that shows HDa1. The split screen will also see a hda1 that you highlight and choose the delete button to totally remove the current Linux installation.