windy1,
First try to boot into Safe Mode. See if you can get Win2k to load fully.
If that does not work, then try a Repair with the Win2k CD.
If that does not work, then you can still try to install Win2k on top of itself.
Each of these can be done without destroying all your data.
Let us know what happens with the first two, do not attempt the third option without posting here first, since if it is not done right, all your data will be lost. (If you can get in with Safe Mode, then stop there, if not try the Repair.)
Take Care,
Richard