Disk visibility issues (internal and external)

I'm having two disk issues, possibly related to each other. Both started recently, maybe at the same time.
Windows 7 Pro x64, SP1, on ASUS G73Jw laptop

1) external USB mechanical disk drive shows as "internal storage" in Windows Explorer. Same for all 3 of my USB drives when connected.
2) internal disk drive is not visible to any program when computer is booted via CD or USB (linux or windows), but only when in one of the computer's internal drive bays; the other drive bay allows the boot disk to be visible when CD or USB booted (e.g. PartedMagic, AOMEI utility).

The only actions I can think of at the time were a) enabling then disabling UEFI to try to get a USB boot disk to work (this computer dates to 2010 on the old BIOS), and b) a couple of hard power-offs due to badly formatted CD and USB boot images.

So far there has been no impairment of OS function, all seems to work normally when booted on internal drive. Since I have two internal drives, I tried starting with my 9-month old backup, but no change for problem 1. Seems problem 2 is related to internal drive bay (there are two), and went away when switched. I don't keep both internal drives installed at the same time.

One of the external USB drives was just reformatted to NTFS, but the other two are also NTFS and they haven't changed recently.

For problem 1 above, here is a list of all the fixes I've tried, gathered from some old posts elsewhere. None of these worked.

- remove and re-add drive letter of external drive
- Remove and reinstall all USB controllers
- Disable USB selective suspend setting
- manage page file size for external drive, set to 1020
- run sfc /scannow, no problems reported
- check for corrupted user profile; nothing changed
- in device manger, uninstall the external drive, check for "ghosted" usb drivers, none found
- create a new registry key with the hardware id of the external drive, at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\usbstor
- reflashed same BIOS (latest version from 2011)

The final suggestion I found was to do a system repair using In-place Upgrade, and if that didn't work a total wipe-and-rewrite of the OS. I would prefer not to do either one of these, but as a last resort I would try In-place Upgrade, which is supposed to preserve my files and applications.

I did search on this forum for previous posts but didn't find any new information.

Any ideas or suggestions?

Thanks,
~Bob

Go into File Explorer and see if the external drives show up under Network Places. If they do, you could access them that way. Or, an easier way would be to map a drive letter to each one of them. For example, X:, Y:, and Z:. Then, when you want to access one, go to its drive letter. The only problem I see with this approach is that if you disconnect then reconnect a drive after doing the mapping, the mapping might not be valid any more; you might have to remap them.