sfrewy video on every player I try- out of sync, slow and jerky

[magpie]

Help! Every .avi file I try to play hasa problems, no matter what I play it on- wmp, theplaya, divx player, realone. And they all seem to have the same problem- the audio plays as normal, but the video seems to be missing frames- so much so that on subtitled stuff, I miss whole sentences. Because of this, the action's really jerky. Plus, it takes a few seconds for the video to start., so the audio's out of sync and just gets worse and worse as I play it.

Any advice?

Thanks,
magpie