Okay, so now I'm wanting to watch Donnie Darko on my laptop, and I've recently upgraded my windows media player version and it comes to an error message saying that I can't play it because -
From experience, WMP has always been sketchy for playing DVDs. Try using another player, my recommendation is VLC. www.videolan.org
Yeah, I would agree with Neil here. VLC is a much better DVD Playback program. I was having problems playing DVDs cleanly on WMP but I downloaded VLC as advised by a friend of mine and all the problems were fixed.
Or you can get a big Codec pack. like DivX or something, I recommend "K-Lite Codec Pack" because It includes DivX and lots of other ones, making any media program you have able to open and view any audio/video file type there is basically. After a few new computers and wipes, I always re-download it and love the codecs.
I'm a step ahead of you Will, I already did that as soon as I realised WMP was dreadful to try to play DVDs on last night