I recently got a new anti-virus prog for my PC, should I delete the Norton that was prev. on my system?

i previously have had Norton on my system as my anti virus, I also still have the Free AVG version, but my norton expired and I saw one featured on Dr. Phil, by PC Tools, So i got the spyware w/ anti-virus and the registery doctor as well. Seems to take a LONG time for it to scan my system, but was wondering if removing Norton was a good idea ?