How do I get rid of this karagany.a trojanhorse on my laptop?

I accidentally clicked on something that downloaded it onto my computer, and now I am unable to open the programs that I had open at the time I contracted the virus. And whenever I search something on a search engine and click any hit, it takes me to the same website and that website goes to another website and so on. I downloaded AVG onto my laptop and have been trying to do a full scan but by the time it reaches a certain point the computer reboots itself. There was one time it completed but found nothing, but the computer's still doing the same stuff. One time it showed the blue screen of death and restarted itself. I started my computer in safe mode and don't know what to do next. What do I do???