Sony DRU 710A won't co-exist with teac 512-EB

My iomega zip drive got the “click of death” so rather than buy another, I decided to install a retired Teac CD-512EB and keep a CD rom disc in it just for backing up my Quicken software.
When I clicked on open or explore, the Sony DRU 710a, would open. When I clicked on open or explore, the Teac said insert disc.
I went to device manager and “uninstalled” the Sony and the Teac would behave normally when I clicked on it. I reinstalled the Sony, but now when I clicked on the Sony, I got the message to insert a disc.
BTW, if I insert a disc, it still tells me to insert a disc.
I have tried about every combination of primary and secondary, master and slave combination I can think of.

Here is my present configuration:
Windows XPpro with SP2
Sony updated to latest firmware
Teac update to latest firmware
Sony is primary slave
Teac is secondary slave

Both units show up in device manager
Both units show up in “My Computer”
Properties say both units operating normally
I can select eject and open the trays on both units.
I can play audio discs on both units, even the one asking for a disc.

Whenever I uninstall and reinstall a unit, the presently installed unit works normally and the newly installed goes into an insert disc mode.
I could just use the DRU 710a but I am lazy and just want to keep a disc in the Teac permanently until it is full.
I would even consider another CD or DVD writing drive if I knew it would co-exist with the Sony.