My home network is doing my head in and I hope someone might be able to help and save me from a nervous breakdown.

The network comprises two desktop PCs, 2 laptops and a Canon wireless printer. The PCs are both running Windows 7 Professional SP1, The laptops run Windows 10 Home 21H2 build 19044-1706 and 1904-1586 respectively.

A few days ago I found I could no longer see one of the laptops on the network. This has turned up totally out of the blue. Until this I've not had any problems communicating across the network since I set the laptop up about 3 years ago.

I've found that none of the machines currently show any of the others in the Network sidebar of the Computer page nor in the Network page if I select if from the sidebar but they must have done so at some point in the past because I created shortcuts on the desktops which still work - all except for the missing laptop. If I double-click the shortcut on the PC for this laptop it times out with a Network Error message offering a diagnostic. If I run this it reports "Problems found - your computer appears to be correctly configured but the device or resource (network computer name) is not responding". The same thing happens if I click the shortcut for the PC on the laptop.

There are a few things that might have a bearing on the issue, but they may also be red herrings: Once in a blue moon the second PC starts up invisible from the first one and needs to be rebooted to get it back. The second is that a couple of weeks ago the printer became unavailable from the first PC but still worked from the second one. I ran some of the networking diagnostics and it reported the Homegroup settings had been "refreshed". After that the printer was back. Finally the laptop disappeared at the same time it was downloading a monthly update, although this had not been installed. Now it has been installed it hasn't made any difference.

I've checked the advanced network and sharing settings on all the machines. Network Discovery and File and Printer sharing are on in all of them so I'm at a dead loss. I thought I had a rudimentary understanding of networking but I'm now totally confused and don't know where to go from here.

I'm posting this also on the Windows 10 forum as I don't know if this is related to one of the operating systems.