MAME32 Video set-up question

I am wondering if anyone in the forums happens to have a set-up similar to mine and how they went about setting certain video settings.

I have my MCE box connected to a Sony 65" rear projection TV running from a AIW9800 card. I am connected via component cables. Media Center runs great and I like the look and feel. However, the issue comes about when trying to run MAME and other emulators. Is it a setting in the front end that controls how big the video of the game appears on my TV? I have this big TV and the game only shows up in 1/4 of it. I am really stumbed about where to go next. Physical connection or software?

Thanks.

Are you using a MAME front end? It will be helpful to know which one and which version you are using. When your PC is hooked up does that take 100% of the screen? If so, you might just need to adjust the video options in MAME. If you are using a front end like MAME32 you can go into the default game options and adjust the resolution it plays in. It is probably set to play in a small resolution and your TV isn't capable of auto detecting that it is different than the PC.