Did you defragment it or did you DEFRAGMENT it? Ever since Windows Defrag ruined one of my disks I have been using O&O Defrag, which works a LOT faster (2 hours for a 80 GB partition on a SATA disk, filled with 79 GB of data) and does much better optimation. Get a trial version of O&O Defrag (which is the only defragger I can recommend, sorry) and defrag your disk, THEN try again. Also, you might want to create an image of your disk with a working, freshly installed Windows on it, so that you can get back to the "fast" state easily.
Cheers, Sebastian -- "If it was two men, the non-driver would have challenged the driver to simply crash through the gates. The macho image thing, you know." - Marc Clifton