Using the Windows command prompt to register / unregister DLLs using regsvr32 isn't much fun. These steps will allow you to do this from Windows Explorer:
- Create a shortcut to regsvr32.exe and place it in your SendTo folder (e. g., C:\Documents and Settings\Administrator\SendTo).
- Create a similar shortcut in SendTo and add -u to the end of Target:

The shortcuts will appear on your SendTo menu, just point at a DLL / OCX and Sent To register or unregister!

For another approach to this see http://blogs.technet.com/jhoward/archive/2006/04/20/425726.aspx