Help! Getting downloaded .avi to play at 16:9 on a 4:3 tv (with setting options)

I'm truly desperate and I would greatly appreciate any help available.

The dealio:

DVD player: A Samsung BD-D5700. You can read about it here, and there's a link to download the instructions in .pdf format.

Plays downloaded .avi files off of a USB stick--but here's the problem. The downloaded .avi files are of shows in 16:9, and the tv is 4:3.

Regular DVDs that are in 16:9 play just fine (with black bars across the top and bottom). But downloaded .avi files that are in 16:9 only play in 4:3. The problem (I'm assuming) is that the .avi file does not have the "this is a 16:9 file" information encoded for the DVD player to read.

The TV is an ancient Sharp CRT that only has RCA inputs, so we can't use HDMI connections. However, it has four screen settings to choose from: 4:3, 4:3 full, 16:9, and 16:9 full. We've tried 4:3, and we've tried 16:9 full (which seem to be the only options). The player is new, so we're not entirely familiar with what kinds of options we have.

If anyone has an automatic "Yup, I know how to fix it" answer, that would be great.

If anyone is willing to go the extra mile and download the instruction manual pdf, that would be amazing.

If anyone knows how to hook up a laptop to the DVD player, and play the .avi file off of the laptop, and you think that will fix it, please let me know.

If anyone knows of a way to *convert the .avi file into something that will fix it*, I am willing to do that.

Please, please, please help. If you can't, but you know someone who might have an answer, please send them over?