Error again: "Symantec Service Framework encountered...."

Error returned again after uninstall/reinstall:  "Symantec Service Framework encountered a problem and needed to close."  Used Norton uninstaller.  Reinstalled Norton Internet Security 2011.  After a couple of good days, the messages are all coming back as soon as the computer starts.  I am running Windows XP SP3.  No other antivirus programs installed.  For now, I am not closing the little window so Norton doesn't shut down.  I appreciate any help.