Resolution of display dropped to default size
I had good display resolution for a while after installing Ubuntu 10.04, however it changed to a default size of 800x600. I cannot adjust it any higher than 800x600 in display settings. I am using a Samsung Syncmaster 2243 display.
Video is a Radeon HD6450 and motherboard is MSI990FXA-GD80.
How can I troubleshoot the display?