I'm hoping Malwarebytes will sort your problem as it is very good. However I was advised that Trojans apparently can still reinfect as you are cleaning them out. The advice to start in Safe Mode is good as I had to do that to rid myself of a couple of trojans. You may have to go into the registry manually to delete them but if you do be careful. If Malwarebytes doesn't solve your problem can I recommend the PC Advisor Helproom Forum who have taught me the little I know! Really helpful people there too.

Good luck - its a shame there are people in the world who use a wonderful resource like the wb to spread evil & extortion but I suppose that is the way things are