I have an HD monitor and an 8800GTS and am curious how I go about watching movies and other stuff in HD format. I have everything hooked up correctly, my issue is that if I download a game/movie trailer that is supposed to be HD, WMP doesn't seem to make it look much like HD compared to the non-HD. However, when I view the trailers that say HD through Azureus, I can tell a huge difference with how crystal clear everything looks.

I also use windows media center, but that seems to be just a different version of WMP. Do I need to get a different type of player to fully use HD format? And also, if I want to watch a DVD as HD, can I get away with buying the HD version of it (not BluRay) and will it play? I haven't had any luck finding an HD DVD drive for computers, so I assume they can run HD?

Thanks in advance!