I think this is an explorer.exe virus, not sure how I have managed to get it myself as I have an activated Norton Internet Security running all the time, plus windows defender, plus windows firewall.
I have done a full scan through Norton, Malwarebytes, Spybot S&D in and out of safe mode and none can find anything! There have been times where I have started up my computer and the pop up hasn't shown up at all, computers been running fast, no problems. However the times when I do start up my computer and the pop up "pleaes remove all ity.im ads from your website" does show, my explorer.exe starts taking up a huge amount of memory and my computer starts to run much slower than usual.
This started happening about 3, maybe 4 days ago, right after I installed quite a lot of windows updates.
I have also noticed, the more I close this pop up the more memory my explorer.exe takes up! I tested it out and it went from 300,000K all the way up to 1,700,000K until I stopped closing them.