found this at another site, not EXACTLY what is needed, but is starting to point in the right direction.
You need to unregister each file with regsvr32.exe before removing the file. An easy way would be to use a batch file. You can get a list of your codecs on the clipboard by using GSpot (View > Installed Codecs > Video, r-clk any codec and select Copy All to Clipbboard). Syntax: regsvr32 /s /u [filename]
(/s: silent mode - only error messages)
(/u: unregister - as opposed to register)
This will unregister each codec from the system, after which you can remove the files without worrying about them coming back.
Hope that helps.