it been running strong for like 3+ year and this just came up around when i updated 3 main program which is window defender kb915597 ,nvidia driver,and steam. I noticed whenever i starting any program it went from 5%-50 to 70% then it came back down->(random usage) and unstable clock also causing my high cpu temp, before 45C now around 50-55C
first use msconfig and turn everything off in start up other then the anti virus and see if it stops. if it does then it a program running in the back ground. i would then turn on only what you need. a lot of time people have flash..java updates running at start up that are not needed.