Problems with video playing on my TV?

I'm trying to watch an .avi file on my LCD TV with windows media player through an RGB cable. The video plays perfectly fine on my PC, and my desktop shows up on the TV as well, but as soon as I start WMP, the TV says there's no signal. Normally, the video automatically goes intro full screen mode on the TV(but not on the PC), but now it just goes away. This is frustrating because it was working just fine a few days ago, and I didn't change any settings, but now, all of a sudden, it won't work for whatever reason.