When I do a fresh reboot kubuntu, everything's great.
When I leave the system on overnight or for several hours and come back to it, the system is not right.
PROPERTIES OF THE FREEZE-UP:
1) Shaking the mouse upon returning to the PC immediately brings monitor back on.
2) Mouse works fine.
3) I can move the windows for apps around the screen.
4) For everything else I might try to do, it's as if I've got a PC of 1/100th the speed. Attempts to load apps are "never" successful, measured in human patience. Clicking things on the internet if a browser is up go at 1/100th the speed if at all.
5) Only way to get out of it is with power switch.
Is it possible that ubuntu is just plain not designed to manage being left on properly? I do some computer graphics, so I need a distro that is competent when it comes to handling a long render.