I also have been using CCleaner for years; but had been LAX in updating it. Recently I decided I should update. On installation the main screen would LOAD but no buttons were active. To stop it I have to use Task Manager. Thinking it was a new problem, I found a site with back level download. I tried 3 Version 5 releases, same issue, then downloaded and installed 4.19 (the oldest version I could find) All exhibit same problem. Currently I am attempting to UnInstall 4.19 (using Control Panel) That process is hung in the middle of uninstall). I use AVAST anti-virus, have an active system monitor Mooo and am evaluating Wise 365. My intent (if I can get 4.19 UnInstalled is to re-install current CCleaner in safe mode as Administrator then try to run it. I am running Win 7 Ultimate 64. Would appreciate any other suggestions.