Flash Player V11,6,602,171 plugin keeps crashing

[Guest]

I have Version 11,6,602,171 of Flash player, which I upgraded to.  I unintalled old version and installed new version, and installation was successful, and I verified that.  But even before I did that it was crashing, both on Firefox and Internet Explorer.  I did recently upgrade to a new version of Norton Anti-Virus software.  Could that be causing the problem?

[Rondo145]

I just upgraded to Norton Antivirus 2013, and suddenly my Flash plugin (11.7.700.202) in Firefox started crashing as well.  It's OK in Opera, which uses the same plugin.  My temporary work around is to use the Flashblock plugin for Firefox, which helps keep pages with Flash from locking up.  If you find anymore info, let me know please.