Get rid of virus?

For the past few weeks, this computer has been constantly plagued by the Conficker.C worm. This is very difficult to get rid of, and even until today, it’s still in the system. I have tried several anti-virus and anti-malware tools such as Malware Bytes, Spybot Search and Destroy, Microsoft Malicious Software Removal Tool and SDFix. All to no success. How exactly am I gonna get rid of this virus? Maybe I should just re-install the XP system. Or reformat the hard drive. I am still at a loss at what I should do. I will still keep on trying whatever method I can find online. Reformatting the hard drive is my very last option. It’s tedious work. And will eat up a lot of my time too. *sad*