"Input Not Supported" for FCEU After New Monitor

[noapparentfunction]

Hey guys, I had acquired a nice 19" LCD monitor and installed it in my cabinet after having a sub-par 17-inch Compaq display in there. My only problem is, ever since I plugged this new monitor in, NES games do not display when being launched from MameWAH.

I run Windows at 800x600 and MameWAH's wallpaper at 640x480. It's funny that MameWAH works, even though the Control Panel doesn't have 640x480 as an option. Everyone's monitor is different, and so are the messages that show up, but when I go to launch FCEU the screen goes dark and the monitor throws up an "INPUT NOT SUPPORTED" box bouncing across the frame.

I went into FCEU to see if I could switch the resolution it ran at to something else. It originally was set to the NES' native res, "320x240 Full Screen" and worked fine. Even more maddeningly, when I open FCEU without MameWAH and run the games, they're fine. I changed it to various resolutions and MameWAH refuses to let it show up.

I checked some of the INI files to see if MameWAH was trying to change the emulator to some impossible screen configuration but I don't know what it is.

I can post any config file you guys might want to see. Thanks in advance for any help!