Hi bretheart,
First of all let me tell you svchost.exe is not a virus. It is a file that allows the networking processes on the system. If u remove it, u will no longer be able to connect to internet. These Days there is a virus with name SVHOST.exe which also affects yahoo messenger. please try terminating that process in task manager and remove it from system startup from "msconfig" command. Then go to C:\windows\
and remove the svhost.exe file and then go to C:\windows\system32\ and remove the same file if it is there and finally restart your system. I would suggest you to use Avast Antivirus. You can get it free from www.avast.com

Do let us know if u still face any problem.

Mark David
TWI ADMIN