Please give us a little more information. Which Service Pack for XP do you have installed? Are the video problems only when viewing videos online or does it also happen when viewing video files offline?
If you're using a dial-up connection and viewing videos on the net, it's very common for streaming video to be poor on WMP and RealPlayer. Because the data transfer is slow with dial-up, you'll frequently get the audio but not the video. Your solution that is to get a faster connection.
On the other hand, Quicktime pre-loads all the video BEFORE it plays it. It doesn't actually stream the video. As a result, although it takes a long time to download the video portion, it plays fine and looks good.
Hope this helps.
Recently I have had problems with video in windows media player, and real player. I've downloaded all kinds of codecs and other tools but still All I get is a blank screen. I have xp and installed a friends hard drive with her version of xp on it and everything worked fine. Can anyone help me find whhat I'm missing? Do I need another version of xp or what? Quick time does work if that helps anyone.