Why don't you just rip your DVD movies to your SD and be done with trying to watch movies on your Wii via DVD.
You don't have a burner? Did you buy your PC in the last century, like in the 90's? Every PC has a CD/DVD burner, I rip and burn upto three movies to a single disc (not saying how though) and my Wii can read... Though my Wii reads all my DVD's, including Dark Knight which I watched just the other day.
All with avoiding the cIOS crap, listen to BlueCrab.
With the problem of your DVDx, I would say to re-install after deleting (using
Any Title Deleter to delete).