Kind of scared to use one yet, cCleaner Pro installs OK but so far I just use it's cleaner, Acronis True Image for backup works fine.
Generally speaking i've always found CCleaner to be good but i'm not sure why you should need it so quickly after installation?
if someone installed the 3.5 framework would there be obsolete files left behind?as i noticed when i ran the c cleaner one, a lot of the errors were framework ones?i selected to clean them all,took the chance of it being a good or bad thing to do.