Have you tried booting into Safe Mode?
With the device powered off, press and hold the Volume Down + Power buttons together. When the Note start up screen shows, release only the Power button. Keep holding down the Volume Down button until it is booted. You should see Safe Mode on the bottom left corner of the screen.
If you suspect an app that is causing the issue, you can uninstall it in Safe Mode. You cannot use any apps except the default ones that came preloaded in the Note I believe. This might help troubleshoot the problem further.
To exit Safe Mode, simply restart the device as usual.