How can i get back lost files
 

I lost the files that I have downloaded.... Is there any way to retrieve them

Look in your recycle bin. If the files/folders are there, you can restore them.

If not, check out this thread: DELETING FILES FROM LIMEWIRE LIBRARY-DON"T! - File recovery advice!
:)

I checked there not there... checked that already...

Changed hard drive lost all files

The Files are saved to your HDD. Not in Limewire or what ever client you use.

They should still be on the old HDD unless something catastrophic happened.

You could hook up the old drive as the slave drive and transfer them to the new master drive.