Just to make thing clearer and simpler.
You can have more than one partition per disk. I have one disk (80 Gb) with some partitions :
1) NTFS partitions for : XP system files, Windows Programs, and Data (which contains *.doc, MP3, ...)
2) Some EXT3 partitions for my Red Hat 9.0
LiLO / GRUB are not really impacted by the format of the partition from which you would like to boot. I mean Grub can start and boot one of your OS without taking into account the file system that supports the OS. In order to remove Grub / Lilo and come back to a single OS computer, please have a look at this ...
I did this some months ago ... and everything ended OK.
But instead of removing Linux, maybe you should try to remove Windows
Hope this helps,
Do not hesitate to ask for more informations,