Vista won't play videos

I'm working on a Compaq Presario Desktop that has Vista and it won't play videos for very long. For instance, when I try to watch a video from Frontline.org it starts but then it just freezes up. When I was working on it from my house it worked fine, but at my friends house it freezes. The only difference is the monitor, speakers, keyboard and mouse. I don't know if it is a hardware or software problem.

 

Both of our network connections are from Time Warner cable. His may be a little faster, but I think they are the same.

But yes it is with the same computer.