"DEVICE=\windows\system32\drivers\TSYCDROM.SYS /D:MSCD001"
This line is only used when one needs access from DOS. It's NOT a good thing if you want proper speed from a CD/DVD drive in windows.
I'd remark it out.
Bob
The subject DVD-ROM is combined with a floppy disk drive on my Dell Inspiron 7000 notebook computer. It quit working about ten days ago after completely playing a movie. When I began to play a second, I began receivng the "D:\is not accessible. The device is not ready." error message. This happens with DVD and data disks. I can only right click the drive and eject. The floppy drive is located below the unit works fine.
I no longer have the original Inspiron system installation disks. All I do have are the Windows 98SE CD Installation files on the C/hard drive.
After reviewing the system troubleshooting documentation I downloaded from Dell, I *think* the problem lies with a file called "tsycdrom.sys" which was not on my computer and seems not to be included among the Windows 98SE OEM files. As Dell does not offer the file nor the "program diskette sets" referenced in the documentation on its site, I downloaded the file from DriverGuide.com. However, they give no clue as to where it really goes on my system.
Exhaustive Google and other searches have left me with the following Autoexec.bat and Config.sys file entries:
AUTOEXEC.BAT
rem - By Windows Setup - C:\windows\command\MSCDEX.EXE /D:MSCD001
CONFIG.SYS
LASTDRIVE=Z
DEVICE=\windows\system32\drivers\TSYCDROM.SYS /D:MSCD001
NB:the drivers folder under system32 was the only place I found with many other ".sys" files, so I put it there.
Still, the drive fails to work. And, yes, I have repeatedly tried removing it from Device Manager while in Safe Mode, letting Windows rediscover and install it, checking and unchecking the DMA and Auto Insert Notification boxes on the Propeties of the drive, updating and scanning with my antivirus and spyware detection software, using the 98SE boot disk from Bootdisk.com, checking the registry for and finding no instances of "NOIDE," etc. The Toshiba web site says the drive will work with the drivers supplied in Windows 98SE but, like the Microsoft Knowledge Base, offers no clues as to where they are or how to find, extract and verify installation. Right clicking Install on the mscdrom.inf does nothing.
I don't/can't believe the drive has failed since it has been rarely used, is still recognized by Windows and I can eject disks placed in it. In any case, the drive is no longer stocked nor sold by Dell (same holds true for the notebook's battery which no longer accepts/holds a charge, but that's an issue for another day).
All help and advice is most welcome and appreciated.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic