Those damn things do more harm than good. Your post was hard to read due to lack of paragraphs. Have you run any scans for malware?
Dafydd.
First of all, I never encountered PC problem like this... I'm quite fammiliar with computers and problems that accure on them, but this one is just twisting my mind and I can't seem to find a solution. Everything was working perfectly for months, every now and then I do a clean windows installation to refresh the PC. On one day (after clean installion of Win10) and normal installion of latest drivers my PC became slow like a snail on THC. Icons began to drag around, Chrome would load pages for ages, in World of Tanks or any other game I would get 30fps.. I tried reinstalling the windows again, same problem occured. I sent PC to service (as I still had warranty and had no time to test all the components). It turned out that CPU was faulty. I was happy to hear that and once PC came home from service, same problem happened. I did clean windows installion and voala, problem was fixed? Yep, but only for a day and then again, same thing again. I sent PC again to service as my problem didn't seemed to be fixed, they tested every component and sad that hardware wise PC is ok! PC came home again, and again same thing, I tried everything, rolling back to older drivers, downloading drivers after clean installion with Driver Booster, disconneting every periphial that could or have some kind of software in it that could maybe on some stupid way ruin the pc performance, but nothing, same thing all over again. I bought new motherboard (not expensive one) just for testing, and problem is still here. I tried with different GPU, problem is still here.. Temperatures are cold as ice, and every component was tested and its working as it should? So what the hell is the problem? I ran out of ideas and I'm beging to get crazier and crazier by a day and thinking 'bout buying new PC... I even bought SSD and same thing happening...
Intel i5 4460 6mb cache 4x 3.20
AsRock Anniversary Z97 Pro
Chieftec smart series 700W
Kinsgston Fury 2x 4gb 160hz
Seagate 1tb 7200rmp
Ssd pny 120gb
(New motherboard I bought just for testing)
Asus h81m
I would be glad if anyone has any kind of idea what could be a problem? And why the hell it works perfectly sometimes for few hrs and then again starts behaving like a snail? Even though everything was tested and temperatures are ok...
Thanks!

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic