Hi I recently downloaded a few video pod casts to watch and the video is all messed up (sort of thing where the driver is wrong) the screen is out of sync and mainly green with no viewable image, the sound plays ok. I also checked past casts that I had previously downloaded, that used to work, they are the same. I have re-installed iTunes, but with no effect. Is this a known problem and are there any fixes? Any help appreciated, thanks.