Norton Anti-virus quit working in Windows XP

Hi, after I first installed my Norton anti-virus 2010 (Nov 7,  2009) in 32-bit Windows XP home edition, I periodically got messages that it was not running; however when I looked in the [Processes] tab of the task manager I saw it running and was able to get info about threats it had blocked.  I no longer get messages that it is not running but I now see messages that it failed to load in my security event viewer; in addtion, I no longer see it in processes; and I can no longer see threats it has blocked.

I have a product key but did not save it online; I do have a backup of one part of it; but need to back up the common files.

Should I unistall it and try to reinstall it from my backup; I assume it is a registry problem in software and/or other registries that is making it not load.

(I did have some virus warnings at about the time I noticed it had quit running; these were not from Norton -- they looked like Windows warnings but may have come from any source including a web forum I was browsing at the time.  Maybe I moused over something by mistake that activated all the popups even though I had my popup blocker on it was set to allow minimal popups; so I shut the computer down; deleted that user account; and have had no more warnings or problems; but can't get Norton to run)

 

Thanks.

 

--C. E. Whitehead