Ive had sooooo many problems upgrading to Windows 2K esp. when converting to NTFS from FAT32.  
I dont even bother with upgrades anymore.

I just hook up a hard disk in a firewire/usb cradle and copy everything to the HDD in the cradle.

Then I do a fresh install and copy it back.

Doesnt take very long if you use firewire and is alot less painful than an upgrade.