Win 8.1 feels unresponsive and stutters

So i have upgraded my system from win 7 to win 8.1 and i've had problems from the start.
After i've had installed my drivers i rebooted and the system woulden't even boot anymore, just a black screen with the blinking White underline. I then did a system repair and it started, but froze and restarted on login. After some fiddeling around in failsafe(don't really remember what i did) it would let me login again.

But now the entire system has started to stutter and feel unresponsive in pretty much Everything. Like when right clicking on anything the entire system sometimes completely stops for a couple of seconds and then resume. The strangest thing i've noticed is when i hover over the start button the entire system freezes for a couple of seconds too and then resume, and for some seconds after that i can hover over the start button and click it and i works, but if i then do something else like click on Explorer the system once again lock up for a Little while and then resumes. This stuttering occurs randomly in pretty much everthing and it's extremely annoying ofcourse.

i've noticed from taskmgr that when i hover over the start button Explorer.exe's cpu usage jumps up after the system starts moving again and when i click on something else System jumps up.

I've tried all kinds of things.

i have no idea if this helps but from my eventlog i have some warnings and errors like
The driver \Driver\WudfRd failed to load for the device SWD\SensorsAndLocationEnum\LPSensorSWDevice.

Some event 27 involving my intel Ethernet adapter

A whole lot of event 10005 that i have no idea about

some event 14 about \Device\Video1


I am completely lost and would really apreciate some help. Just ask for something and i will do my best to provide information! My system should be in my sig right? (First post on this forum)