Thanks for the assistance, folks. DavidR, I had the 4.8 (I think: blue ball icon) free; I did uninstall the old version before installing the new version, even restarted computer between. I tried manually inserting key, and also tried following instructions from site and just clicked on license file to 'automatically insert into the program,' but no luck.
YoKenny, I turned Avast's firewall off; I only want it's anti-virus service (which by the way, how is the firewall working if it won't accept the license key?
Man, you folks are speedy. Thanks for the quick responses.