How do I uninstall a Windows installation from a dual boot setup?

[Jeff7181]

I'm dual booting the WinXP x64 preview edition and WinXP Pro. I would like to uninstall the preview edition of x64 so that I can install the fully functional 120 day trial of x64 before I trade in my XP Pro lisence for an x64 lisence. Is deleting the Windows folder on the partition it's installed on a viable method? Does it need to be installed on a blank partition? Cause I have some data on that partition that I don't want to throw away by reformatting.