Windows 7: Network Discovery OFF, but can still see other PCs on network

As a consequence of starting down the Win10 course I've had occasion to go back and look at my network settings on my Win7 PCs (1 x desktop + 1 x lappie).

Now, when I first set-up the network settings on the Win7 PCs I also had some XP machines on the network so I did not use HomeGroup in Win7. Rather, in Win7 Network & Sharing I set network as 'Work' so as to banish HomeGroup. I know that originally I had Network Discovery turned on for these Win7 machines.

In setting up the 1st Win10 PC I noticed that the Win7 PCs had Network Discovery turned OFF (but had no difficulty in accessing [or being accessed by] the other Win7 PC or the Win10 PC shared resources). So I tried the same on Win10 - but Win10 point blank refused to access the other PCs without Network Discovery ON.

I know I could try turning Network Discovery on for the Win7 PCs (and presumably that should still work). But I'm a bit perplexed as to why things work with Network Discovery turned OFF under Win7. Can anyone shed some light on why it actually works with Network Discovery OFF on Win7? I realise that it probably isn't that important - I'm just intrigued.

The other network settings are:

File & Printer Sharing: ON
Public Folder Sharing: OFF
Media Streaming: OFF
File Sharing Connections: 128 bit
Password protected Sharing: OFF
HomeGroup Connections: Allow Windows to manage

As an aside, I'm a bit surprised by that last one (HomeGroup Connections) as my understanding was that using a 'Work' network was meant to banish HomeGroup (I've never had to actually set-up a homegroup). Maybe there has been a change somewhere along the line since I set-up the Win7 PCs in 2013/4.

Hello Batch,

do you have Windows Firewall switched on?

NetBIOS discovered will find other PC no problems

Thanks for the replies.

@iko22: Using Comodo Free Firewall, so Windows Firewall not on for Win7 machines, but on Win10 machines using a 3rd party FW (such as Comodo) certain vestiges of Windows FW are still enabled (by MS design).

@samuria: NetBIOS is enabled on both Win7 & Win10 machines (by default). But my clear understanding was that with Network Discovery OFF one would not be able to see other computers or be seem by them. Reference materials tend to state this quite clearly (without any reference to exceptions and the like).

What happens if you temporarily turn off Comodo Free Firewall and use Windows Firewall, anything?

Haven't got round to playing with the FWs, but I just noticed something today.

I happened to run Speccy (from Piriform, the Ccleaner people). It shows Network Discovery as "Enabled", but Network & Sharing Centre still shows it as Off.

So which shall I believe? Maybe I'll just go down the pub.

Pub for one or two is always a good choice!