Crawling Speed Task Manager Shows 100% CPU Usage

I've got this problem 2 days ago where my PC started slowing down and i've been getting random BSODs mainly "Special Pools Detected etc & Memory Management" When i start up the PC its slow and it takes alot longer to just open even a folder. I've tried searching for such problems and i've tried almost everything i know to try and fix this but i guess i'm still in-experienced when it comes to problems like this.It happened 2 days ago after i played an online game i got a BSOD and couldn't remember what it was. So i restarted and the problem started. The most recent hardware change was that i changed my RAM from 4gb to 8gb and nothing else. I did not install any new programs recently. So initially i thought it might be the RAM causing this problem so i changed it back to the ones i had previously. Here are the specs of my PC. [code]

Anyway i've scanned the PC using Avira, Spybot & Avast and there were 0 findings so i hope i am right to assume that my computer has not been infected with malware/spyware. But still in the task manager, the CPU Usage % and Memory Usage shoots up whenever i do any sort of action, eg. Refresh on the desktop, Opening a folder, Opening the browser etc. I've tried booting into safe mode. And the CPU usage was minimal compared to normal but i couldn't detect what was causing this problem. In the task manager, explorer.exe & svchost.exe were the top memory users. I've tried msconfig, disabled all the startups, but still i am having the same problem.