[wlug] Dual boot

I have previously configured a dual boot system with Grub using XP (FAT32) and linux with no problems. However, on my main computer, I tried XP (NTFS) and Linux with disasterous results - lost my whole windows disk. I am keen to try and load Ubuntu concurrenly on a separate disk on my main XP computer but do not want to loose my bills etc. Has anyone successfully dual loaded Ubuntu on an XP machine where the XP is NTFS? Alternatively, can one convert NTFS to FAT32? Cheers John