Let me correct my following statement:
Windows 8-B and W7 are logged in by the same ID and password, but Windows 8-A is logged in by a different ID and PW.
". . . but Windows 8-A is logged in by a different ID and PW" is actually ". . . but Windows 8-A is logged in by a different ID but the PW is the same as others for logging in to W8-B and W7".
I changed the PW to one being unique for the ID used to log in Windows 8-A and the problem is resolved. I did this for trouble shooting purpose but still do not know why the same PW caused the problem. Could anyone explain why?
Please note that the ID/PW for the Windows 8-B was the same as that for W7 but there was no problem accessing Windows 8-B even before changing the PW.
Edit: This problem has been resolved.