Problem opening Firefox, Internet Explorer & other problems

On Monday morning, 9/21/2015 I was able to use FF 37.0.2 & IE 9.  After leaving the PC idle most of the day I  discovered that FF would not launch.  Tried IE and it too would not launch.

Today after not using the PC for several days, I find that MS Word and MS Outlook also no longer launch.

PC shows no signs of any hardware faults.  OS is Win 7 Pro SP 1 and is patched through 9/16/15.

A review of system event logs shows each of these various launch failures and the logs all indicate Norton Internet Security\NortonData\21.1.1.7\Definitions .... .(Current Norton NIS version is 21.7.0.11)

A scan of the affected programs does not indicate any files being changed in the involved timeframe.

A scan of various Norton files shows numerous files being updated throughout the day on the 21st.

Any attempt to launch any of the programs referenced above result in a Windows popup report such as "Firefox has stopped working".  Selecting the option to check on-line for a solution results in nothing being found  and a reference  #0x80000003 which provides nothing useful (NOTE: all affected program produce the same reference #).

 

Is there any way to determine what changed in Norton to cause this problem?

or

Is there any other way to resolve this problem?