Xvid need help please?

What happened to online movie streaming? Now everywhere I look it asks to download Xvid or some equivalent. I used this site quite frequently a few year ago it's watch-movies.net . So far I have looked for answers and it seems others have the same problem before but still nothing worked. When I opened the link it asked me to download Xvid. So I did and rebooted and yet nothing. It just says the same thing as if u didn't download Xvid. I have also tried downloading media players to include wmp and vlc. My pc has widows vista and I use Firefox as a web browser. Hopefully someone has figured this out. I have also uninstalled Xvid and reinstalled it. Otherwise I would say in my opinion Xvid is a wash. Please help.