How do I remove this trojan horse virus?

Well it originally was one trojan horse but now it's turned into a bunch more. Basically what's going on is whenever I do a google search and click on a hit, it takes me to the same website and that website goes to another website and so on. And my computer does random restarts, and I can't open in safe mode anymore. I've used AVG to do full scans and it's quarantined them in its virus vault but it's still acting up. So I downloaded Malwarebytes and did a scan and clicked 'Remove All' and it said they were removed, but it's still doing the same stuff. And now AVG and Malwarebytes are not finding anything, but I know there's still viruses since my computer's still acting up. How can I actually get rid of the virus?