[Samba] Win7 pro trust relationship failed

[Dave Beach]

Out of the blue, after working flawlessly for years, I suddenly cannot log
on to my samba 3.5.6 domain with one particular Win7 Pro workstation.
Nothing has apparently changed - Win7 updates applied recently, but I was
able to successfully log on after that. Nothing has changed on the DC.

Error message is that the trust relationship between the workstation and the
primary domain failed.

I'm reluctant to drop the workstation from the domain and re-add it for fear
that this may somehow compromise user access to files on the workstation; is
there any chance there's a forehead-smacking simple thing to check and fix?