i downloaded some files but when i clicked on them they did not open

If you're trying to play them via LW then that's probably your problem. Use a different player.

You may have downloaded bogus or mis-named files.

This topic is covered many times in the forum. I am not able to link you to the threads right now (tech prob) but you can search for them. You might want to start with Getting Started Using Limewire in this forum.