Hi there and welcome
Power off the mac
Then start the Mac and hold down the Command and R keys at startup.
Hold these keys until the Apple logo appears. After your computer finishes starting up, you should see a desktop with an OS X menu bar and an OS X Utilities window
choose Disk Utility from the Utilities window, or from the Installer menu if you're started from an installation disc.
Click the First Aid tab.
Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.
Select your Startup Disk (usually named "Macintosh HD").
Click Repair. Disk Utility checks and repairs the disk.
Let this complete and when it has, tell me if you still have the problem please.
No problem at all, let me know how it goes please
Thanks, ***** ***** do the following please
Then tell me if it now freezes again
That can cause an issue, and we can confirm this, trash Norton so it is uninstalled from the computer.
Does it then still freeze?
ok, please let me know the results. Though unless you purchased Norton, I would advise on using Avira instead. Norton causes more problems then it solves.
But let me know how you go please.
ok, but run it a day without norton just to see if this is the case.