I did a clean install of Windows 7 RC on a Dell 1545 which had been running Vista Basic.
All was well except that the DVD writer vanished from explorer and Device Manager at random intervals.
I re-installed the Vista Basic and the drive worked perfectly. I backed up the driver
so I have a cdrom.inf and cdrom.sys from the working Vista system
I then upgraded the Vista system to Windows 7 and sure enough the DVD drive problems came back.
I cannot find a way of replacing the Windows 7 driver with mt nice working Vista driver.
I can't update it as Windows 7 says the current one is the best, I can't delete the driver because apparently I need TrustedInstaller permissions, I can't give myself permissions as Windows 7 doesn't give me the option under the security tab on the driver folder.