Is it peaking at 100%, ONLY after doing Windows Update and / or immediately after rebooting after doing that? Or is it doing it all the time?
If it's doing it all the time, it almost certainly means you have malware on there.
If it's doing it only after doing Windows Update, then it may just be what it is. WU can get a bit piggish these days, especially on Win7. Also, that MakeCAB.exe may indicate that Win10 is being downloaded to your PC. MS is pushing it out to everyone that has Windows Update set to Automatic, whether or not they want it or have it "reserved". (MS being a bully to their customers, as usual.)
You want to know a solution to this Windows crap? Easy, drop Windows completely.
http://www.linuxmint.com/
Download and burn an ISO to a DVD, boot off of it, and try it out. If you like it, or think that you can live with that, then install it to your HDD. But by testing out a LiveDVD ISO, there's no commitment.