Invalid format on big screen

I have what I hope is a simple one.
The game plays fine in my 17" Monitor but will not play on the 42" Big screen TV. The Internet work fine on the big screen and when I try to load the game it comes up a black screen and invalid format is on the screen.It did work o.k. on the TV.It is An LG 42".
What Could have I changed? I have not found it yet.
Thank you for your help

What is the native resolution of the 17" monitor? (Probably 1280x1024)

What rez do you have GW set to?

Do you change your desktop resolution when you connect to the TV?

The main thing I can think of are that the resolution of GW is not supported by the 42" TV. (which is why it says invalid format) For that to happen, you would either have to be changing the desktop resolution when using the TV, but no changing GW's res, or, if you are leaving the desktop at 1280x1024, then your GW is set to some other un-supported rez.

So, basically you need to set GW to a screen rez that is supported by the TV, or maybe, play in windowed mode (if you were playing full screen).

Best guess is that GW is set to an unsupported resolution; if you play in windowed mode and it shows up correctly, this is almost certainly the issue.

What's curious, however, is that most (all?) LCD TVs should have scalers that can handle anything from 480i and up.

Thank you folks.I had to change the resolution on the game up one step and every thing is working again. Good job