your computer is very likely the problem.

Try uninstalling your codecs and installing ffdshow alpha. Depending on what speed pentium 2, that might or might not make stuff watchable. I know my roommate used to watch anime on his old 450, but he had to stay in ffdshow-land or it would do exactly what you're talking about.

You might consider getting a new system sometime soon though -- they're not too terribly expensive these days for stuff that's massively better than what you have [img]i/expressions/face-icon-small-wink.gif[/img].