When the desktop hangs or freezes, are you able to switch to another terminal screen (tty) via the following?
You can get to tty3 by pressing Ctrl+Alt+F3, tty4 by pressing Ctrl+Alt+F4, tty5 by pressing Ctrl+Alt+F5 and tty6 by pressing Ctrl+Alt+F6.
You can try whichever but it should switch you to a console/text prompt.
If you can login there, that might let you snoop around to get clues.
To switch back to the GUI, press Ctrl+Alt+F2.
Unfortunately, I’m not really sure what to look at first for this kind of behavior. You might see something in the X server log but what to look for, I am not so sure.
Someone might be able to chime in for what would be good to look for.
I think the problem is a corrupt disc. I have loaded and run Lubuntu from Disc and have not had the problem. Thanks for your help.