I can't preview my downloads.
 

I can't preview my downloads. Also my videos and music won't play in my computers default media player. And yes I did shut off the LW default player.
How can I fix this?

Sounds like you need codecs, see CODECs list and alternate players for Movies

The problem is I couldn't preview my downloads. They would play in my default player but I couldn't play them buy launching them through LW. Also my FAQ and forum options didn't work in the help menu. But I fixed it but downloading the offline installer instead of the recommended install. But thanks for all the help!