OK it is a known issue, you may also receive a Flash crash as well. Google, Norton and Adobe are all working on the issue. It is quite a complex issue and there have been released updates which fix the problem for some (not all) users and they are continuing to work on this problem.

Make sure you have the latest updates for all of the above.

For Norton run Live Update and apply any updates which are available. Re-run Live Update until you have all the latest updates.

Chrome should automatically update however if there are any available you should see an arrow on the Tools button (wrench icon), click that and select Update Google Chrome. Restart when prompted.

Uninstall all instances of Flash Player from Control Panel > Add/Remove Programs. Restart the computer then install the latest version from http://get.adobe.com/flashplayer/

After making sure all are updated test to see if the issue has been resolved. If not then as a workaround you can turn off the Identity Safe feature of the Norton Confidential plugin from within Chrome. With Identity Safe turned off you may experience no crashes or less frequent crashes. Each time either of the above programs have an update applied turn the Identity Safe back on to test if the issue is resolved.

It is also a good idea to make sure that Windows is also up to date with the latest patches. Visit Windows Updates and check for updates, apply all that are available (you may need to restart the computer several times). Return to Windows Update after each restart and check for more until none are available.

You might also consider the use of free program Secunia PSI which monitors your installed programs to make sure you have all the latest versions. Secunia PSI can be downloaded from http://secunia.com/vulnerability_scanning/personal/ This program would also help identify if you still have an older version of Flash Player installed, this is quite common and can cause problems such as yours. If you do see an older version of Flash flagged in PSI then run the Flash uninstaller from http://kb2.adobe.com/cps/141/tn_14157.html then re-install the latest Flash Player.