3ivx only with quicktime?

hi ppl. got a question and since im a total noob at this stuff i hope u can help.

just downloaded a movie in 3ivx format. i got the codec and it works fine, however only on the quicktime media player. its the standard free version so no full screen which is annoying.

does anybody know a media player that doesnt crash when playing 3ivx file?? windows media and bsplayer both crash

or maybe convert 3ivx to XVid perhaps? (and if so..how lol) please help

thanks alot