Several things to do: If its a new TV, then I presume you have HDMI, 15 pin analog video monitor, VGA and S-video input receptacles for it. Likewise, the laptop has a VGA at least and S-video and most likely a 15pin VGA analog monitor output.
Choose the hookup you can get the best resolution from (Analog monitor/projector most likely), use the correct cable, then use the TV remote to scroll thru the list of alternate input signals on the TV and select the proper one. Then you need to go to Vista Control panel/Display to select the output port (S-video, analog monitor etc. Sometimes one of the function key sets (Fn + f4) is enabled to switch between the laptop screen and the analog monitor or VGA outputs. The are actually 3 settings in the Fn selector: 1) the screen display only, 2) the alternate output only, and 3) both screen and alternate output. This has to do with alternate monitors, presentation projectors, power saving options (the laptop screen takes a lot of power).
You might also have to change the resolution of the display settings in order to match the capability of the TV. You can do this for just the alternate monitor (TV) output, so that when the TV is used, it looks good, and when the laptop display is used, it also looks correct.
Then get rid of Vista and upgrade to Windows 7. It will give you a desktop icon to select that will make all these changes for you by sensing the cable you plug it. Vista does this too, but you have to create the icon and shortcut yourself.
I bought a cheap laptop with an HDMI output port. You should see TBN on a 47" display in 1080P. Actually you can port it to the PIP (Picture in Picture) selector and watch your TV channel AND do the TBN all at the same time. My PIP frames are bigger than my monitor, so its a win-win for me.