I'm using ubuntu 12.04 and everything was fine until today. I've tried to run a windows game trough wine, the game started but crashed back to the desktop and after that the screen resolution went to very low. I've got to monitor settings and fixed the resolution to the native 1400x900 and it worked fine until I rebooted my computer. Now instead of the greetings screen (lightdm) all I get is an black screen with the monitor's "out of range" message. How can I fix this ? I Have a RADEON HD 5800.