Before going the nuclear route of reinstalling, I would try scanning for viruses. There are some out there that do exactly what you are describing.
Try Malwarebytes and or ComboFix, which are free to use and have served me well.
If that doesn't do it, or they don't detect anything, then try removing a stick of RAM and see if that helps. If it's still doing it, replace it and remove the other stick. If the problem goes away, you either have a bad RAM slot or bad RAM stick.
If you are still having problems after that, and the logs do not reveal anything, I would seriously look at contacting your manufacturer and get a new one because likely the MOBO is bad.