This might be of interest........
I treated myself to The Wizard of Oz dvd this Xmas. Digitally remastered, 3 dvd set, £8 from Virgin or HMV, forget which, absolute bargain. Was going to spend Christmas Day trying to see if there really was a dead Munchkin hanging from a tree in there somewhere. try to play it on my Dell computer with sonic cineplayer - absolutely nothing. No other dvd would play either.
Solved the problem today. According to Dell, the player won't work if the date is December! Changed date, prob solved.
Mother-in-law had same problem. Built her a PC for xmas pressie, would not sign in to MSN messenger. Reason was the date was in the past too.