Several people have had problems with their GUIs freezing when they try to copy large files using FileCopy(). This is because FileCopy() is a blocking function, and the GUI stops responding to messages from the OS during the operation. If that goes on long enough, the OS thinks it is hung and you get the (Not Responding) thing going on. Here's a function that copies large files using Windows API calls in 8MB 2 MB chunks. This keeps the GUI alive and responsive. I've added additional copy ve