How to Fix a Samsung LCD TV "PC Mode Not Supported" Error
Samsung LCD televisions have both HDMI and VGA ports. These ports allow you to connect a PC to the Samsung and view the computer's screen on the TV. Once connected, the computer screen should be visible. If there is a problem with the connection, a "Mode Not Supported" error will display on the screen. This typically occurs because the screen resolution hasn't been configured on the PC properly to allow the signal to be read by the Samsung.
Right-click in an empty spot on the Windows 7 desktop.
Select "Screen Resolution" from the menu.
Choose the "Resolution" menu and move the lever up or down to "1024x768."
Select "Advanced Settings" and hit the "Monitor" tab.
Choose "60 Hertz" under "Screen Refresh Rate."
Hit "Apply" and "OK."