Device Manager Error Code 42 - Duplicate Devices

I've got several external USB drives, and for some unknown reason, two of
them are in a condition where only one is recognized by the Device Manager at
at time. The first one mounted will work, the second one shows up only in
Device Manager with a yellow flag, with the following message on the
"General" tab:

"Windows cannot load the device driver for this hardware because there is a
duplicate device already running in the system. (Code 42)"

The recommended resolution for this error in the MS Help and Support Site
(article ID 310123) is:

"A duplicate device was detected. This error occurs when a bus driver
incorrectly creates two identically named children (bus driver error), or
when a device with a serial number is discovered in a new location before it
is removed from the old location.
"Restart the computer.
"On the General Properties tab of the device, click Troubleshoot to start
the Troubleshooting Wizard."

Restarting has not helped. The Troubleshooter gives up after a restart fails
to work. There doesn't appear to be anything indexed in the Knowledge Base
that relates to this problem or how to correct it.
Anyone have a clue how to redesignate one of the devices so both will be