Where does Windows get info for "Network Map"

I have a small home network with 3 Windows 7 machines. I like to look at the "Network Map" now and then.

It changes with different routers and it even changes with different firmware on those routers. Last night I turned off "Homegroup" and now Windows cannot see ANY machines on the map. My network "works" fine. I have all computers sharing what I want.

I am asking "Where does Windows get it's information for the Network Map" so I can get the map working again. I already tried turning "Homegroup" back on, but here's what I get. (left) and what it looked like before (right) (I renamed it but settings are the same)

It gets its information by sending out a broadcast and listens for a reply from any supporting systems.
Link Layer Topology Discovery - Wikipedia, the free encyclopedia

Thanks logicearth, that tells me where to start. I don't know where to start diagnosing this. It could be the "mapper" or the "responder"

It's the same on all network machines, but I still don't know where I would start.

Funny that my network works fine but this would suddenly become a problem. It may be a prelude to bigger problems is my fear.

Thanks for the info.

jfar said:

I know this might sound stupid but, have you turned off your machine and turned it back on manually ,not Reboot ,
since you turned off Homegroup, If you haven't try it and see does it help.

I shut down all one machine. It did nothing.

I then shut down all machines and turned them all back on manually.

Windows 7 is now showing the full map.

Thanksj jfar, it must take a full start-up to re-detect the machines.....

SouthSeaPirate said:

I take it that it wont work for non-7 machines?

Works for Windows Vista, and Windows XP SP3, or for those XP Machines that install a hotfix.