When I try to use the "Clean" feature the progress bar goes all the way across and just stops. Nothing happens. No files show up in the box, which remains blank. It doesn't lock up or freeze the computer, it just does nothing. The other features such as "Issues" work fine though.

I uninstalled CC and then upgraded to the latest version, 1.23.60. It is doing the same thing.

I am sure the boxes for what you want to clean are checked? Try saving a couple of cookies, make sure there is something to delete and try again.

I haven't used CC for about 4 months so there are plenty of cookies... I think the problem may have started after I tried to upgrade from ZoneAlarm 5.5 to version 6.0 It didn't install, froze the computer, then the BSOD. The computer did weird things for a couple days like freezing up, ect. Now everything works OK except CC's "clean" function.

Try uninstalling and re-installing CCleaner. It sounds like that crash damaged the program.

Wouldn't hurt to also revert back to ZoneAlarm v5.5. I also had the BSOD, the inability to install, and a whole host of other problems when I installed version 6.