Basically I was backing up my friends Windoze PC using my external HD to transfer files to a different computer (he just got an iMac). Unfortunately, while I no longer need the files on my HD, I can't get rid of them completely. Many files ("My Documents", "Application Data") are locked and although I know how to deal with this from a linux perspective, I don't know how to do it from a Mac perspective. I've tried cmd-shift-option-delete, I've tried pressing the option key while clicking on "Empty Trash". I've also followed the instructions on the Apple website (http://docs.info.apple.com/article.html?artnum=106237). I'm not really sure where to go from here. I'm running Leopard (10.5.1) on a MacBook Pro 2.33GHz if that's relevant. Thanks in anticipation.