WMP = Windows Media Player, he already said he downloaded that.
VLC is great. It'll handle almost anything. But you can also get things to play in QuickTime by downloading
DivX and
3ivX, and maybe
XviD. But VLC will handle all that without downloading anything extra. The sites I listed are only if you want to play stuff through QuickTime. Even then, VLC will generally handle those files a bit better.