smss.exe doesn’t stop when shutting down

When logging off, shutting down or restarting, I get an error message saying the smss.exe hasn’t stopped running and then I have to hit the End button to get it to shut down or restart.

I just resently got the GRAPS virus and successfully removedall the infected files according to the instructions. This just started since the infection. I re applied SP4, but it seemed to make no difference. Anyone have ideas?