Video files that play very choppy, but sound ok...

I keep downloading a series of t.v. programs, and also some other movies that are very choppy, and then some of them stop playing video all together, though the sound works fine. Is there something that can be done to repair these video files, is it my system, or are the files just corrupt? Your help is greatly appreciated. Thanks.

http://home.hccnet.nl/h.edskes/mirror.htm
try the klite codec pack full

give us some more info.

what player do you use?
do you have codecs installed?
pc specs?