I try to preview a movie that I'm downloading from limewire and it opens Windows Media Player with a message like: "The file is already in use. Close other programs that might be using the file, or stop playing the file, and then try again." I tried pausing the file or stopping it but I still get the same message. How do I do it?

That's interesting. I wonder if someone is uploading it. Have a look in your monitor window, that will tell you. Quit wmp & try again. OR/And try another video player. You do have a backup player don't you?!

I only have WMP. Where do I get the file? In some temporarly folder I guess.

The incomplete folder. Go to LW's Library window, select the incomplete folder & press the Explore button. This will open the folder for you. That's if the file hasn't finished downlding yet. Otherwise it will be in the Saved Files folder.