Workgroup Name Resolution Not Working

I have a LAN at home with 4 computers on it. They are all in the same workgroup, and all except 1 work fine, but on 1 computer i have the following problems:If i click view workgroup computers, it says i do not have permission to acces it, even though i have my workgroup set the same as on the other 3 computers. If i type the name of another computer into explorer like this: \workPC it says it cannot find it, while on other 2 computers it works (and on the 3rd too of course, since that one is called workPC). Also remote desktop connection doesn't work if i type in workPC, but it works on the other 3 computers.
But the other 3 computers cannot see this 4th computer either, it doesn't show up when i click view workgroup computers. It's as if it wasn't in the workgroup, even though i've triple checked it and it's the same as on all other computers.I can, however, access all other 3 computers via IP, like \192.168.0.5 and such, and that works, it also works via IP for remote desktop connection.

The problem that bothers me most, though, is that i cannot remote desktop into this 4th computer, even though remote desktop is enabled and it should work. I can remote desktop to other 3 computers from this computer, but not the other way around. When i try to connect to it (via IP since it doesn't work via it's name), it asks me for the username and password. I enter those correctly, then i get a warning i always get (something about "Remote Desktop cannot verify the identitfy of the computer you want to connect to." (and so on)). After i click yes (*i want to connect anyway*), it just returns me to the window that asks you for the name of the computer to connect to, and that's it.