I'm fairly new to Ubuntu and Unix based systems as a whole. So far, my only concern is that my graphics cards are not waking from sleep (hibernate?) mode. When I move my mouse or hit a key on my keyboard while it is in sleep, I hear my CPU and case fans turning on. However, I do not hear my GPUs. I have two HD Radeon 6870s with AMD's proprietary driver installed from their website. I am also running Ubuntu alongside Windows using Wubi.
Any help would be much appreciated.
This sounds similar to a problem that I have occasionally. When it happens I am able to get the graphics to show by pressing Ctrl+Alt+F7 which goes to the terminal that your desktop loads on. I have only my integrated graphics card so I have no idea if this will works for your gpu cards. If the next time this happens Ctl+Alt+F7 does not work, this should get your desktop back but it WILL close all your running programs and restart your desktop so you will lose any unsaved work that was open a the time the computer suspended.
Press Ctrl+Alt+F(2-6, any will do) to get to your other terminals. enter your username and password at the prompts. after you are logged in type the following:
you will get a message that says lightdm stop/wait then type:
this will restart your desktop and then go to your log in screen or straight to your desktop if you have it set for automatic login.