Only Audio No Video on Windows Media Player

Hey I just started getting a problem where when I click on a video to watch it from a website it opens up my windows media player but then all I get is a still picture of the beginning of the video and then the audio plays. If I click on the link again after this has happened once for the same video then it will play. I have re-installed Windows Media Player 10 but still have the problem. I am running Windows Xp on a Dell Inspiron 600m. Anyone know where I can look for help?