A few basics, you haven't said whether these have been set. You need to make sure the windows 7 machine network settings are either "home" or "work" network location, and file sharing is enabled. The workgroup name also needs to be the same as the SME workgroup.
I did set it up as a "work" location, enabled file sharing and put it in the correct workgroup and still nothing worked at that time.
I am
somewhat happy to report that it suddenly started working without further intervention on my part. It worries me when I don't know why something wasn't working, let alone when it starts, seemingly on it's own. The only thing that I know has happened was a power-cycling of the ethernet switches. Being three hours away from the site, I don't know if there was some cable-switching happening in the middle of this mess that might have confused the switches.
The main thing is that it is working the way it should have from the beginning.
Thanks to all for your help.