I've just upgraded from XP (32 bit) to Vista Business (64-bit) on my AMD 64

It was done as a fresh install, yet left the existing files and directory
structure as they were (which was a nice surprise).

However, I've decided to remove Cygwin - but there's a small (30 Mb) section
of it that I can't delete running either as a user or an administrator
("Access denied"). This section consists of files (perl modules) that were
built and installed while running as the user ("Rob") on the earlier XP

Any advice on how to remove the last remnants of Cygwin from this machine ?

In installing Vista, I was prompted to create an administrator account. I
initially chose the name "Administrator" but was told that it was already
use, and that I had to choose another name. (I chose "Admin"). In addition
to that I set up a user account ("Rob"). They are the only accounts I
created. I wondered whether there might be something to be gained by running
as this elusive "Administrator", but so far have not found a way to do that.