Cant see networked computers after windows update?

After windows recently updated on one of my win7 machines, i can no longer see the other 4 computers on my network. 2 win7 Pro machines & 3 XP, all in same workgroup. I can see the affected win7 machine from all the other computers and can even access its files, the affected machine can connect to the internet as well but i cannot see any of the others.
Network discovery is on, but file and print sharing is not and when i click it on and say Save Changes, it does not hold the change; also under: my system settings-system properties-computer name the Network ID button is grayed out so i cannot change my workgroup name even if i wanted to. I am logged on as admin.

Any one have some ideas? Thanks.

I have to ask...did you/have you rebooted since the update?

Yes, many times, after each thing i tried that i thought might resolve my issues.

Remove PC that's in question from the joined network and then rejoin....

I cant change my workgroup name as stated above.

I don't want you to change it, just leave the homegroup and then rejoin.

Attachment 20595

Not in a Homegroup, belong to a workgroup of which i cannot modify.