Could not install update on my all-in-one Dell computer machine.

[stevef]

Open a terminal session by pressing three keys:- Ctrl Alt t
In the terminal window run two commands, entering your password when asked for.

first

Code:

sudo dpkg --configure -a

then

Code:

sudo apt --fix-broken install

Then try updating again.

You should run updates more often.  Additionally you may wish to consider tidying up some of the older and unused kernels you have on your system.  This isn't contributing to your current update problem but it will free up some disk space.  Take a look at Kernel Remover under Lite Tweaks.