I think the key word here is "conflict". Norton is a selfish and jealous program and can cause more problems than fix at times.

System Restore may be a good idea, but if it were me I would be uninstalling Norton and rolling with one of the generic, less obtrusive programs like AVG or the others that Jo has listed numerous times.

I also think that with all the ongoing software and performance problems you have had over the last year, a fresh install of the operating system from your local tech person would be a sanity saver.

Give them a call and see what they would charge, just for giggles.