I have a Windows XP and I just downloaded Limewire. Whenever I try to download a movie/TV show it sometimes works, but usually when I click preview it either says I don't have the right Codec or it opens but flashes green. This only happens with Real Player and the Audio is able to come through. I have three questions

1) Why does it flash green and how can I stop it?
2) Why does it say I have the wrong codec
3) what is T3 and will it download if I have just a fast cable internet connection?

thank you!