Long Loops

I am using a For loop to copy a bunch of files to a different folder, over 1000 of them. Each file is pretty small (10-20kb). When the loop runs, the program seems like it is not responding, although it is still running. The form becomes blank and doesn't update any text boxes or anything. Is there something you have to do when working with long loops, maybe add a delay or something?

call doevents ... perhaps not in every cycle but reasonably often