I bought an player that according to the maker 'supports' Mpeg4 Mpeg2(DVD) WMV and many other Video formats and works in all the OS's however once I actually got it and tried to used it I found out it only support AMV and has a program that converts those formats to AMV. and the program is Windows XP only, so I cant use my old Win98 system for it and I also cant use my Linux for conversion. I tried to contact the company and they gave me the usual bla bla we dont care. so my question is simple how do I convert WMV, Avi and Mpeg4 files to AMV, and also if its possible how do I make other files convert to it aswell (Divx,Xvid etc.) or, if its impossible how do I force my player to use Mp4 (But I am extremely doubtful its possible)

Sounds like a pretty screwed-up system and codec. Wikipedia doesn't have much good to say about it. Doesn't look like there's anything in Linux that supports it either, though I did find indications on the mplayer site that they're working on adding support.

I did find this page that seems to be some kind of open-source firmware project for players like yours. And this page of their wiki explains how to get their converter program working under wine.

Gonna have to remember to avoid these players if and when I decide to shop around for one.

I hope you tell everyone about that company and their policy.

My first reaction was that you should return the player to them, and hope that they go bankrupt soon. :-)
But I guess you've already tried that.

Hope the other suggestion works! And be sure to tell everyone else to avoid those products.