I had a big problem with CCleaner, which I have followed since three Windows before. Never a problem with earlier versions of Windows. Now, with Windows 10 I noticed a strange permanent activity of the disk in the background. I checked with two antivirus programs. Problem continues, sometimes taking complete control of the PC. The only program I loaded before the problem started was CCleaner. I deleted CCleaner with pain in my hart. However, the problem didn't end. Somehow, it corrupted my system. I asked a professional consultant from Microsoft to fix it, and he tried with advanced antivirus tools. However, he couln´t fix it. If you want to see what happens start the Windows "Task administrator" and see how CPU is used very intensively even if you dont start any application. It runs on the background in a frenzy, using as much as 99% of CPU! It is really bad. Hope Pririform staff and Windows staff find a solution to this. In the meantime, the only options that come to my mind are return to Windows 7, or change to a Apple computer. Both expensive. If anyone has a solution to this, please share with the Forum. Tks.