Norton AV using all my CPU

Norton AV is using all my CPU. What does this mean and how do I fix it? Thank you.

It could be that your Norton is doing a catch up full system scan if you have not allowed your system to idle enough to run the scan in the background.

It could also have something with a need to complete an update to Norton or Windows. You can start by restarting your computer. 

Have you run LiveUpdate manually a few times, restarting as necessary, until no updates are available? Then restart again. Restarting, not shutdown and startup again if you have Windows Fast Startup feature enabled.   If you use Windows 8/8.1 or 10, there can be an issue with the Windows Fast Startup feature.. See more information here.