What are your specs?
Have u tried a different browser?
Try installing lattest adobe flafh player version.
Check settings for hardware acceleration by right clicking the video
It may also be your internet speed.
Let it buffer a little then watch it.
im having trouble streaming, videos begin to stutter during play back this has only started in the last week iv got windows xp
here goes, the reasom most of the time is u have to much stuff running & loading at start-up many tab open playing music watch video's all those programs loading at start-up take 50% of ur ram so when to all those thing at 1 time u only have 1/2 ur ram & it could a crash or BSOD, the way to shop those programs from loading is to type in run msconfig hit ok then go to the startup tab in there is where u see all programs with a mark in them they load, so u can disable all but u anti virus don't worry in not getting rid of them it's just stopping them from loading, then do a disk clean-up & a defrag that being the file up front for faster access, delete cookies & history weelky clean out all browsers cache's, resart & ur see ur computer will run smoother than before