How do you kill a VERY smart virus?

OK I am dealing with an extremely smart, under the radar, virus, that I CANNOT eliminate no matter WHAT I do. I first noticed it when my whole PC suddenly got very slow and I noticed I was having weird script errors. Immediately I tried scanning with AVG and it didn't detect anything. So then I tried System Restore, IT ALSO DIDN'T WORK AT ALL. Whatever restore point I set my PC to, it would fail! Then I noticed that my system stand by option had suddenly disspeared so I knew I was dealing with a smart virus. So after a few days of scanning with various programs such as Norton, Avg, Spyware blaster, Microsoft Security essentials, Malwarebytes, avast, panda internet security, and many more! I decided to quit and just use my recovery disc. When I inserted it into the drive I noticed IT WOULD NOT RUN? Why is this? So then I knew it was a very severe rootkit virus so I used an anti-rootkit program called gmer, and whenever I would perform a scan with it my whole PC would freeze until I manually rebooted it, like the virus was messing with the program. So Ive sort of just had to accept this virus until I can get a new PC but I am very worried if my backups my be infected with this bad virus undetectable virus, because if no security software can detect it, the scans will all come out clean. This virus is scaring me. Is there anymore hope I have of stopping it?