This might be simple and I'm overlooking it. I own a MacBook Pro with a multi-touch trackpad and a Mighty Mouse. I'm not sure what I've done, but I can't seem to double click with the touch-pad button or Mouse on simple display icons or songs in Itunes. I've tried everything in Systems Pref. but can't seem to figure it out. 
Any help would be awesome. Thanks
Any help would be awesome. Thanks