After a fresh install of Windows 7 Ultimate on my Gateway P-7811FX notebook, my DVD-RW drive was recognizable in Windows until after a long sleep session. Upon awakening the notebook, the drive was gone. A quick sleep/wake cycle did not have this problem but overnight would knock out the drive until reboot. Microsoft's registry fix or deleting a lower filter entry did not apply to this situation. There was no lower filter entry. I reinstalled several chip set drivers and nothing helped.
Then I installed the Intel Matrix Storage Manager. Happily I have now made it through one overnight sleep cycle and my DVD drive is visible. I thought Matrix was only for RAID and don't remember it being installed on the factory setup.
Bottom line is Intel Matrix Storage Manager is one possible solution for disappearing dvd cd drives in Windows 7.
