That would be located in your Video control panel.
I have an Nvidia card and if your TV is identified you can make the computer primary , the TV primary, or clone.
I usually have to resize the screen on the TV for it to fit, that's why you're only seeing a background image. The start button and taskbar are off the screen until you resize it.
What we need to know are your hard specs.
Look this over and post back:
In order to troubleshoot your problem we need to know more detailed specs of your system hardware.
1. Go to Start > Run, and type msinfo32. then expand the Components tree and choose a device
2. Go to Control Panel > Device Manager and look for any entry that has a yellow flag beside it.
3. Download System Information Viewer
4. Download PC WIZARD 2008
5 Please fill out your computers specs in the User Control Panel here on the site as well. It will then appear next to your name. look at my posting and you'll see the drop-down arrow.