DR-
Perhaps your SETI client is still running as a screen/saver and/or background process. RC5 and SETI can successfully co-exist on the same system when set up with SETI in screen saver mode and RC5 as a background service/process. I believe that Sukhoi, LeBlatt and/or Polo use this system now.
If you wish to run RC5 only, you may want to uninstall SETI completely, but try to do it right after a SETI WU is completed as to not loose any work.
viz