CCleaner has a bug in its module making it wipe %systemroot%\Installer folder even if cleaning of it isn't selected.
Its PITA to get that folder deleted on Windows 7 x64 Pro, since every darn update for .net, vb, c++ etc. fails!
Can't even install Visual Studio after CCleaner did its crap.
Sorry if I sound a bit mad, but it is a shame that such a nice tool has such bug.
I wonder if no one else hasn't reported this yet...