After installing software from Medibuntu, not all dvds play; dvds play only my desktop computer but not on my laptop

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http://askubuntu.com – I installed Ubuntu 12.10 on my desktop and Toshiba Satellite laptop. Then, I installed everything shown on the pages for Medibuntu on desktop and laptop. Now I have 2 issues: the laptop will play most dvds, but there is a great time lag between insert and playback (the dvd drive makes various noises); I have 2 dvds that will not play on the laptop, but do play on the desktop. Can anyone help me with these issues? Thanks. (HowTos)