You should be able to d/load and play video files without problems. LW won't play videos, so they'll launch in you default player.
Check videos with
Bitzi Web Lookup. It'll help you sort out the good ones. While on the Bitzi site, search for the file there and use the magnet link to start the d/load in limewire.
If they won't play then either it's a fake/corrupt file or you need some codecs for it to play properly. You can d/load codecs off the internet or use a player that has the codecs already installed.
VLC media player, has the codecs built in and will play most file types. It's a good player to keep around for those stubborn files that you can't get to play.
If you using windows media player you could try
K-Litecode Codec Pack or
XP Codec Pack 2.0.6.
If your OS is Vista:
Vista Codec Package v4.4.8 (freeware).
Other threads to check out:
CODECs list for Movies/Alternate players / Video help forums/ video-mp3 fixers Fake files showing up in search results Problems with the search How to find music(and video) Setting Default video app