You got it. Now, if you used the administrator tools in XP, you wouldn't get jack done, as the XP disc is active. If you used partition magic or something to try to do it, it would reboot to do it, go into dos, and ATTEMPT to convert it back, but you will always get a weird error. My not being a programmer, I can't tell you what the hell the error means... You also risk data corruption, which might be related to the error, I don't know. So the only safe bet is to move the data, use the XP CD and delete the partition, recreate it, then format with FAT.
Asus A8V Deluxe Mobo
AMD Athlon64 X2 4400 -939
2GB Crucial DDR3200 Dual-Channel
ATi AiW 9800 Pro 128DDR
Sony DRU-810 DVD+RW DL
3 x Maxtor MaxLine SATA 160Gb 16Mb Cache
1 x Maxtor MaxLine SATA 300Gb 16Mb Cache
1 x Maxtor MaxLine SATA 120Gb 16Mb Cache
Make sure that the partition is new, and create it with the CD though, because if it already finds a NTFS partition, it'll want it. Making the native OS do the formatting is probably a good idea as well. If I remember correctly, ya have to make sure you do the 'advanced' settings in the install and make sure to catch it.