Problem with watching videos on my pc

[gizmo.1484]

Over the last 2 days i have been trying to watch a movie on my pc but the stream keeps stuttering. The sound is ok but the picture doe's not play consistent, it's like the movie picture cannot load fast enough for the stream so you get this jerking effect on the screen which is a bit annoying. This is the first time this as happened as all the other times it as been fine as i have a 20meg d/load speed.
So can anyone shed some light has what the problem could be as i have tried a few movies and they are all the same.

[bigboots]

if you using windows xp .go here Half-open limit fix (patch) for Windows - Home and that will open full access full speed to internet