Samsung DVD SD-608

Hi,

my brother has a Samsung DVD-ROM (SD-608), but he can’t change the DMA-setting (unable to change it into “Enabled”). When he plays a DVD-rom the movie shakes.

Can anyone give some idea’s please.
We already tried reinstalling drivers.
Windows (98) also says there is no DVD-ROM in the computer, but a CD-ROM (if this can help)