The CCleaner Pro 5.15 update didn't work on my Win7 Home Premium computer. CC would start, sit there for 4 or 5 seconds, then shut down. I tried uninstalling, re-downloading & installing, same results. I tried uninstalling, re-booting, reinstalling & rebooting, same results. I found the old version, reinstalled it, & it worked once, then it shut down the same way. After about 3 weeks, someone on another forum suggested I try the portable version. I used it, unzipped it, copied it to the folder, & it worked.