It takes a few weeks for antivirus companies to discover new viruses and develop defenses and definitions against them. In the meantime those viruses are running in the wild. There are ways to remove viruses manually without antivirus programs. One is using Process Explorer an application from Sysinternals. I learn new techniques for virus removal because viruses are constantly changing.
Here is an excellent talk by Mark Russinovich. Mark is co-creator of the Sysinternals tools and website and now, after Microsoft acquired Sysinternals, is a Tech Fellow for Microsoft.
This talk tells you how to use Process Explorer to remove viruses manually. It will be most helpful to virus removal and computer repair techs or more advanced computer enthusiasts.