It will require that you uninstall WebLogic, download again, and reinstall. But there is a way to keep all of your work. Here's what I do:
1. Copy your ?/bea/wlserver6.1/config/mydomain directory to somewhere else on your hard drive.
2. Go to the control panel and uninstall WLS. Make sure to delete any directories that still remain.
3. Download the same version WLS from BEA again, and install.
4. Copy your original /mydomain directory over the new one. Provided you reinstalled the same version into the same path,
you should be all set.
joe