NoScript is one of Firefox's security add-ons; no worries, if it's not installed
In regards to the plug-ins:
1) It would be ok to uninstall
Microsoft Silverlight ( unless you use it to view Netflix; other than that, the said plug-in has no other purpose in any site I know of ) -- just a head's up though: be ready to
set your Windows Updater to Manual, because once you completely uninstall Silverlight from your gear, it'll try to re-install it again -- say you have uninstalled it via
Add/Remove programs or using third-party uninstallers like
VSGroup Revo Uninstaller, open your Windows Update, and change the settings from
Install Updates Automatically ( Recommended ) to
Check for updates but let me choose whether to download and install them -- if the UAC prompt appears ( for Admin control ), just confirm it
After that: reboot your gear
Now once it's restarted, open the Windows Updater and manually click on the
Check for Updates -- believe it or not, the Updater will try to reinstall Silverlight several times; just hover your pointer over each Silverlight update that appears, and right-click for the option to
Hide the update ( a UAC confirmation message may appear as well for good measure ) -- it'll try to do this, on my end, around five to six, so Hide the said updates
Once no more updates appear, you can reset the Windows Updater to the default
Install Updates Automatically
2) Since ClixSense needs Adobe Flash, leave that one untouched, but you can disable the Shockwave player ( Youtube fairly runs without it, if you have media audio players installed -- like
VideoLan VLC Media player )
I'm just wondering about Norton's plug-in -- since Norton has a history of being aggressive in scanning sites from one's browsers, I may guess it may have something to do on not viewing any particular section of a webpage; try to drop by the Norton's Forum section and
look around ( strangely, the term used for that phrase is
'lurking' ) perhaps the threads posted in their Forums may help you