Grinds to a hault

Can anyone point me in the right direction for this?
Using Leap15 x64, fully up-to-date, and every now and again, the system will work for hours (being 6/7 or so), then within about 1 or 2 mins, will just grind to a hault - ie generally cannot even log out/do anything. Occasionally it will allow me to ssh in and perform a reboot, but generally no. I suspect it may be either Thunderbird/Chrome, or addons, and thinking that the best attack should be to disable all addons and go from there.
Anyone with similar issues, at all?

Sounds like overheating, to me. Check your air passages and clean them, clean up air fins.

I am not sure, but this thread may be pertinent:

Don’t believe so - monitoring ‘sensors’ intermittently and all seems ok there.

Will check out that other link.