Oddball occasional freeze on Dell Inspiron

[MR ZenWiz]

My partner is running Xubuntu 18.04 on her main computer, a Dell
inspiron 17" laptop we bought new a little over a year ago.  Every
once in a while, usually about once a week, the system simply freezes
up and stops responding for more than five minutes at a time.

Last night we were running a Zoom test between my desktop and her
laptop, and her system froze.  Usually it's when she has too many
Chrome tabs open and one of them locks up the machine.

When this happens, sometimes the mouse will respond to movements, but
clicking on the various items on the screen does nothing.  The
keyboard does not respond either.  I usually give it at least five
minutes before I give up and reboot the machine.

Another oddity with the Dell is that it doesn't always respond when
the laptop is closed and the screen was locked unless we open the
laptop.  It also sometimes does not reboot properly and has to be shut
down to get rebooted.

This almost never happens on my desktop, my HP laptop or her older HP
laptop (which is painfully slow but it functions any time we use it -
the Dell was a replacement for this HP).

Is there any indication that Dells have a problem like this?  I never
see it on HPs or my home-made custom desktop.

Mark