External MAXTOR hard drive not recognized after installing BIOS update for Intel F.56.Rev.A

[Psychee]

Hello.   I have been trying to get my Pavilion 17t-ab200-CTO notebook to recognize my Maxtor 1-touch Plus USB-connected external hard drives that I use for backups.  The notebook recognizes that something is attached via USB but only as an "unknown device", and neither one shows up in Explorer or Disk Management when plugged in.

Both external devices are recognized and work fine in my old XP notebooks, and both were recognized fine and worked properly prior to my installing the "HP Notebook System BIOS Update (Intel Processors) F.56.Rev.A" last week.  The drives are externally powered and the lights are on and I can hear them working when they start up.  The issue is not one of hardware malfunction. 

The helpers at Microsoft seem to think that this BIOS security update might have messed up the computer's ability to recognize these external hard drives.

The notebook DOES recognize a Seagate Backup Slim Plus eternal drive without problem, but that is a newer device.

I have tried the following:

--using each of the USB ports -- all work for other things, and all work for making connections, but none work to get the device recognized.

--looked for updated drivers (none that I can find)

--uninstalled and re-installed twice (with restarts after uninstall and after re-install.  The MAXTOR management software loads, but the device is still unrecognized.  

---was not able to UNinstall the BIOS update

---Maxtor web site no help

---Intel website no help

---thus far, HP website has not helped.  Apparently all drivers are deemed up-to-date.

What have I missed?  What can I try next?  

Thanks in advance