Please do the following: Stop the sshd service and change the args
given to sshd to '-d' (lower case d instead of the usual upper case D).
The start the service again and ssh to this machine. The difference
now is, that you get a listing of the environment variables propagated
to the user shell. Check especially if $PATH is valid and contains the
paths to the Windows and the Windows/system32 directory, both in such a
way that is matching the *system* mount table. If you don't get a clue,
send the output of the environment vars together with the output of the
mount command to this list. Don't forget to revert the -d option to -D
later.
I istalled sshd with