|I don't know who gave you what steps so it'd help if you would post some specs about your system.|
When people say they want to go back to 'factory settings' they usually mean they want the operating system back to the way it was when the computer was first purchased. If that's the case you'll need to reinstall windows either from disk or a restore partition (if there is one) on your hard drive. If you have a restore partition it should show in your boot options in cmos/bios setup. If so, set that as the first boot device. Then save, exit bios setup and reboot.
Of course by doing that you'll also lose all your documents, pictures, videos, and music unless you've saved them on other media.
If you're interested in removing the virus and keeping your OS and files post back on what you know about it (a lot of viruses seem to be in the 'W32' category) and what you've done already to try to clean it up.
message edited by DAVEINCAPS