Just a thought...
Do you have System Restore (SR) enabled?
Might be worth unticking the box and see how that goes.
Vista has a snagette with SR, as it can be a bit of a resource hog.
Click the : Start button| type: 'System Restore' in the search box, and click your way through the offerings.
I don't believe you have a snag with your computer, just that some settings might need a tweak.
Report back.
PS. You still haven't said what CCleaner removes.