the list of servers for this workgroup is not currently available
must be one of the most annoying messages in Windows you could imagine. You have two computers on the same LAN, you can ping, so you know that the connections are right, but if you want to access the files on a share of the other computer you get this message without any hint what might be the cause.
I could try to explain why you just have to set this registry entry
to 1 (instead of the 8 it was set to on two of my computers), but you are probably in a hurry to just access the other file and are not interested in research. If you are interested in the why then continue searching the web. I did and found my answer.
But as I said, you are most likely in a hurry, so set that registry value and reboot, and if you are as lucky as I am then you will be able to see the other machine(s) on the LAN and share happily.