If there is a third party screensaver on there, then there is probably some other sketchy software on there. So along with ccleaner, download malwarebytes and run that too. Also is there any antivirus software installed? Starting to wonder if you have a bug in the system.
It really doesn't sound like a hardware issue to me.
i apparently also downloaded all the proper stress testing and tempt guags in the process to overclock my machine.... watched a few videos, bumped it from 3.1-4.0 and ran prime 95 and monitored my tempatures.... so far so good