New PC can be seen, but can't see other PCs on the network

Hi guys, I've hunted around for a solution, but seem to be at a dead-end.

I have 3 PCs, all of which are installed with Win 8.1 Pro (64 bit).
All PCs are connected via a Netgear router - two via RJ45 ethernet and one via 802.11b/g wireless.
Each of the PCs has the same Workgroup of "WORKGROUP".
The Homegroup services of HomegroupProvider & HomegroupListener are disabled and each PC.
Each PC shares its "My Documents" folder(s) between each other without any issues.

Recently I added a new PC to the network.

It's also connected to the same router, via RJ45 ethernet.
Same Workgroup, same Homegroup services disabled.
Same sharing settings on the "My Documents" folder.
All of the other PCs can see its shares and can read/write to it.
The new PC can't see any of the other PCs, or their shares from within Windows.
The new PC can ping all of the other PCs, so it doesn't seem to be a connectivity issue.

I've ran the Windows network trouble-shooter, but it can't find any problems.
Now I'm basically stuck. Not sure what to check next or what other thinsg to try.

So any suggestions or comments would be greatly appreciated!

Cheers,

Mike.

Leave Homegroup on all computers. Make sure what Firewall software you are using, is disabled. Also you can find information on Network share & setup at EZLAN.NET

Thanks for the reply...

I re-enabled the HomegroupProvider service on the 3 other computers and I could then 'see' their shares from the new PC. However, I still hadn't enabled the service on the new PC and haven't set up a Homegroup on any of the PCs...

It'd be nice to know why it's behaving like this and why the other 3 PCs can see each-others (and the new PC) shares without need the Homegroup services at all...

Mike.