Stability problems with N360 and Firefox Adobe flash player

Hello

sometimes when I double click the Norton 360 icon on task bar, it doesnt pop up as normal GUI, only a completely black screen in Norton user interface, its crashes if I click on it and if I wait Norton 360 never restore itself, if I click and it crashes and then it restarts the n360.exe. so basically norton crashes and service restores itself because its pre-planned in that which is good, so I dont have to restart my PC every time.

However, I want to learn why its crashing, its mostly happens when I have Firefox open at background (flash player open in it) and some other software like Steam and windows notepad. My best guess is adobe flash player, of course its up to date but that piece of software IS a disaster. When I'm on youtube or most pages with video in it, page becames un-responsible and/or my Norton 360 gives me "Heavy Disk Usage" performance alert due to flash player. Everything else works normally

Like I said, crash mostly happens if Firefox (or flash player) open at background, when I double click to N360 icon on task bar, it gives me black screen only in Norton User Interface (not entire screen) and then crashes

Windows 7 64bit, official adobe flash player up to date as well as Java (I have no any other plugins/extensions in Firefox) Norton 360 fully updated 22.5.5.15 -  Firefox 42.0

Thanks in advance