You don't really ever "uninstall" an operating system. You can upgrade it, overwrite it, format, or partition or repartition drives.
But you do know what you are talking about. You are concerned about the bootloader.
If you just remove or replace the Linux drive the bootloader will not work.
I believe in backup boot media and would create a Grub floppy in Suse with "grub-install <name of your floppy drive> (/dev/fd0, /dev/floppy, /media/floppy?), then an
XP boot floppy. Confirm both work. Then I believe "fixmbr" (or is it "fixboot"?) in Windows is the correct command to get rid of GRUB.
If you create the floppies you will be able to boot straight into Windows before any changes and into Linux after changes. Then change your drives when you choose.