1. Video we often recommend VLC player as it has in-built codecs & is reliable for playback. Otherwise try to find the right codecs:
CODECs list and alternate players for Movies
2. Who is your Internet Service Provider (ISP)?
3. Do this test, downld a magnet link from here & tell us what happens in regards to connection & speed:
http://www.magnetmix.com/video.shtml
4. If you're using windows XP SP2 then it might be worth looking into these:
MS & 3rd party patches
5. Do you see a brick wall in front of the blue world icon at the bottom of the LW interface? (see sample attachment image below)