You may also want to try

1- Boot computer in "SafeMode" by hitting F8 right after powering up puter

2- Run antivirus program. (see if it catches and disposes of virus)

3- Reboot (to normal mode)

4- Run antivirus program again (just for yukes)

Safe mode runs the computer with only basic system programs. This keep sophisticated viruses from starting and repopulating on normal boot up.

good luck