It seems that there is unresponsive script works on background . So,Use No script addon to stop unresponsive script. It also because of flash player which is currently in beta ,so using script blocker with a stable version of flash can heal a lot .

Hi. Thanks for your fast respons. When I search for No Script this is what I find: http://prntscr.com/3wc367 and this for script blocker: http://prntscr.com/3wc3dy Witch of them should I use?

use this link : https://addons.mozilla.org/en-US/firefox/addon/strict-pop-up-blocker for script blocker and for no script ,use this : https://addons.mozilla.org/en-US/firefox/addon/noscript

when you use them first allow temporary permission from sites ,then use permanent permission if the problem is not from that page .

Should I remove ad-blocker first if that can interfeer with strict pop-up-blocker?

this is going to kill me, the addons keeps on blocking everything on all the sites I visit.. if there isn`t any better solutions I guess I will have to move over to chrome then because this is to annoying..

see What I said , you have to see which site makes your graphics crazy. Open the site and "allow them permanently" if that site not gives problem .

this is bit tuff but you have to identify and solve them by this .

You have to read this : http://mzl.la/LOwPvg

I will try that guide that you linked to.