extract to any folder (say, desktop), run TaskManagerEx.exe
press ctrl+shift+esc to bring up task manager
select menu extension | find user module
type the offending dll and right click on each listed process then select unload
delete the dll file
if the virus is smart enough, it has many ways of loading itself. so don't be surprised it comes back again. you may also want to run autoruns to find out all modules loaded at startup time. disable suspicious ones.
anyway, manually deleting a virus may not be clean enough. have you tried symantec's removal tool in safe mode?