Ever since I changed to Windows 7 Ive had a problem with CCleaner scan running extremely slow like 2-5 minuets to scan just the windows tab. I have the latest version of CCleaner and have gone back to older versions to see if I get the same problem , well I did. So I went back to the latest version and tried to find out which setting was the problem. This is what i found out. If I un check (in windows tab)Internet Explorer,Temporary INTERNET files, and in the System files, Temporary files the scans are fairly normal. there seems to be a problem with windows 7 and CCleaner and these temporary files. I just use windows 7 disk cleanup for the temp files. Best I can do, maybe someone can fix the problem.
Maybe you have so many options that are checked and maybe you have not done any cleaning for some time so there will be a lot to clean there too. Its possible that you have an application installed that is delaying the cleaning process as CCleaner may have trouble dealing with.
In my own experience, having the "Autocomplete Form History" checked on the Internet Explorer option does make the cleaning seemingly longer for CCleaner. Better have that Autocomplete Form History UNCHECKED.
Slow scans can also be caused by this.