If you have the installation disc for you operating system with the product code you might want to consider wiping the hdd with something like WipeDrive rather than reformatting it. A product like WipeDrive will completely overwrite everything on the hdd including those viruses where as reformatting will only delete the addresses of you files.
Now days you need several types of protection to keep this type of problem from happening. All of the software listed below can be run with each other without conflict, you will have problems if you try to run two different anti virus softwares at the same time...they don't play well together. All of these programs are free.
AVG anti virus http://www.grisoft.com/promo/download-avg-75-free-free75cnv/
Spybot Search and Destroy http://www.majorgeeks.com/download2471.html
Adaware http://www.majorgeeks.com/download506.html
Asquared http://www.emsisoft.com/en/software/free/
You will also need a firewall like Zone Alarm http://www.filehippo.com/download_zonealarm_free/
If you have a CD or DVD drive on your computer you might try downloading these programs on another computer and then transfer them to your computer. Start your computer in safe mode and run your scans there, you may be able to get rid of your infections by doing this.