Computer slow and application hangs

Am running Norton IS 2009.  Last few days computer has slowed/stopped and applications hang up.  Symantec Error Reporting suggested several possible causes/solutions.  Tried them all and only successful when I disabled IE add-ons, OCSEngine Class, ver 2009.0.1.0 and Symantec Intrustion Prevention, ver 9.0.5.0,  both installed or enabled by Symantec on 8/22/2009.

 

Feel unprotected at this point not understanding what the files do and the need to "fix" a problem of slow computer, etc. at the same time.  Hopefully there is a patch to fix.  Would appreciate any suggestions or "fix".  Thanks ...