i've burned a DVD on nero before, and it worked. but now, it won't. i clicked "add movie file". and added the file. the blue line on the bottom (showing how much memory is on the DVD) moved, but the file name didn't appear. and it just froze up. i let it sit there for a while, hoping it might start working again. but it didn't. so i tried to burn a different movie, to see if it was just that one file. that also didn't work. i retry it tons of times, but it always freezes up. does anyone have any idea what is wrong?