Perform a thorough uninstallation (preferably using the SH3 disk) and include the SH3 folder in your MY DOCS section.
I'm unaware of how good 'TweakNow' is but I would advise using 'crapcleaner'
http://www.filehippo.com/download_ccleaner
(tis free) or even better still the one of my personal choice 'regvac'
http://www.regvac.com/fregvac.htm
This is not free but there is a free trial version available from the above link.