I will make the assumption that since you are dealing with virus infection you have a Windows machine. Do you have the disk and codes necessary to re-install your software? If so I would back-up any important data and then format the drive and re-install your programs. Now before you do anything else download and install a good free firewall--Comodo and Zone Alarm are two that come to mind but there are others. Next download and install a good free anti-virus program such as AVG Free or Avast. With all of these programs use care that you download the FREE version as they all have versions that require payment. Now after the fresh install of the OS and the firewall and anti-virus you can reinstall your data from your backup. Make sure your new anti-virus program checks it as its installed to remove any virus that may be hiding in your data. At this point you should be good to go--just make sure you keep your firewire and anti-virus programs up to date and in use. Good luck Ralph
At home, I use a copy of Symantec Antivirus.
I also regularly use the freeware Spybot Search and Destroy. (If you use Spybot, please consider supporting them by making a donation! They have been working tirelessly on the product for years, always completely for free.) It's saved my computer many times.
Best is to get one of these bootable CD/DVDs with a minimal Linux and a bunch of antivirus progs on that automaticly update over the internet. Since you booted from the optical drive the virus scanners can detect malware sitting in the boot sector of your hard drive. Here or here you'll find working CD images. Try a little google search on the subject and you'll find lots more. Sometimes you find them as giveaways in computer mags.