Joe, It makes no difference as long as the driver name is the same in both the config.sys and autoexec.bat lines. Drive E:? What drives do you have in the computer and how are they connected. Is the hard disk partitioned (drive C: and D:)?
When you see "CDR100 not ready to access,” click Retry a couple of times. The CD-ROM may not have had enough time to spin-up. Try another CD. If you are accessing the CD-ROM from Windows, go to the Control Panel, System, Device manager, Delete the CD-ROM drive driver, reboot, and see if Windows has detected it and reinstalled the driver. If not, go to Add New hardware and see if Windows will detect it. The CD-ROM drive may be defective or the laser lens maybe dirty. You can buy a cleaning kit at a Radio Shack, etc., but I have found that most of the time cleaning does not fix the problem. Given the speed of the CD-ROM drive and its likely age and use, the most probable cause of the problem in my experience is that it has died of old age. Larry