Download this:
http://www.superwin.com/regvac.htm
There is a free trial period version and is far more potent than CrapCleaner (which doesn't deal all that well with the deepest registry files but is good at most other cleansing operations).
You will need to do a fresh install but use the disc function to do that, not forgetting the SH3 folder in C\MyDocs of course.