Dell Laptop M6800

Dell Laptop M6800:

This is a very high spec laptop
RAM is 24 GB and 40 % in use
CPU 8% in use
DISK is around 10%
Windows 10 Pro
The problem I have is that the laptop becomes unresponsive after being left on for 2-3 days
The mouse keeps sticking over icons and juttering and the audio and video keeps buzzing and sticking - both on the internet and local sources
If I stream the audio to another device the audio is fine so it looks to be a local issue

I have all the latest drivers, have run malwarebytes and ccleaner, cecked all antivirus programs etc - no improvement
I work in IT so know my way round computers
Any ideas?