1. Go to hp.com and see if there are vista drivers for you sound and video items. (and install those!)
2. That green screen issue that is often cured by hardware acceleration is a sign of a missing driver 99% of the time. The other 0.1% is a missing codec. I'd run VLC PLAYER to sniff that out.
Bob
I recently upgraded to Vista and am having major issues with audio and video playback using windows media player. The audios and videos won't play properly. It first had a green screen which I thought I fixed by turning off graphic acceleration. But even with it off, its having problems. Now it lags or doesn't play at all. Even other programs like iTunes won't play songs. Also, online clips such as sample audio clips or CD previews. Someone please help before I chuck this laptop out the window!
Oh and I have an HP Pavilion dv4030us.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic