Is NAV 2014 incompatible with XP Pro Sp3?

As of August 28th .. NAV 21.5.0.19 crashes repeatedly on my XP Pro (32-bit) computer.  Basically, NAV stops, relaunches and then I have another crash.  And so on...

 

Moreover, I can't start Firefox w/o an error message (close down).  On my 2 Windows 7 computers, running the same NAV and Firefox versions, no such problems.  They run fine.  See also my comments here:

 

http://community.norton.com/t5/Norton-Internet-Security-Norton/Check-Your-Norton-Vulnerability-Protection-for-Firefox/td-p/1173387

 

Upshot: I unistalled NAV and cleaned the computer with Norton's 'removal' tool and reinstalled, all according to Symantec's recommendations.  I did this twice to be sure.  However, no joy.  Same crashes/issues with both NAV and Firefox.

 

Question: is NAV no longer compatible with XP?

 

As I'm tired of the situation and not interested in chasing error messages I removed NAV and installed a free scanner.  No crash and no issues with anything so far.  Firefox runs just fine!  I'll return to NAV once I know it works again.