What version of Nero do you have installed? The only real way to remove Nero from making it the default video player is to uninstall it. This should return it to the prior default player. Just remember when you insert a DVD movie to play just make sure you don't check the box to "saying make this the default player" the next time it pops up. Also we don't know what O/S your using and sometimes changing the file association can restore it to the right player default.