I have been using a Plextor 48/24/48A for some time now and have had no problems whatsoever.
The other day I noticed that PX-755A units were really quite inexpensive so I purchased and installed one.
The precence of the two drives seems to have caused a problem because, as soon as I insert a DVD, my computer shuts down completely and the DVD has to be removed manually (if a DVD is left in the drive the computer will not boot up at all).
Booting the computer produces the bios set up screen on which there is an error message about CPU speed. (the computer is not overclocked).
Can anyone help me out here??