no no no..........leave windows alone!!.
uninstall edition,
delete the Pinnacle folder especialliy pixie in programs, remove any pinnacle folder in my documents and c:\ documents and setttings\ your username\ pinnacle ( if it exists)
then run regedit ,
back up your registry
then try to remove ALL traces of Pinnacle software.
Enlist the help of a friend if this seems daunting: it can be
Then reinstall this time you should be prompted for your serial no etc

Certainly reinstalling windows (if it is relatively clean and you dont mind) will achieve the same effect but it is overkill if you can avoid it
You may need to go to windows explorer options and check unhide files in order to find the folder/s with pixie in the subfolder of documents and settings

Pixie and the Registry entries are the things to remove to get a clean pre first installation state back.. It has works but registry editing can be tricky
Good luck