hillol k bala

My windows 2000 does not seem to be accepting my DVD-ROM (NEC 5700A) drive
anymore. everything has been working for the last 2 years. last week i was
trying install something from the DVD-ROM, and when i restarted the machine,
there was no DVD-ROM drive in "My Computer". when i checked the Device
Manager, there was a yellow mark in the DVD-ROM device icon. i uninstalled
and reintsalled the device thousand times, but i'm still getting the yellow
mark and drive is missing. Windows can detect the drive and can install it
successfully, but when i restart the machine, i always get the yellow mark.
i could not find any driver update for the DVD-ROM. when i see the
properties of the device from Device Manager, i got a message that says
there is something wrong in the registry. i tried to delete DVD-ROM entries
from the registry, but it did not allow me to delete all the entries.

Can anyone explain what's going on? what should i do to resolve the issue?

thanks,

Hillol