Workgroup Not Accessible

At the moment, I cannot see other computers on the network, nor can they see me.
Please help me to 'see' my computer and to allow other computers on the network to see my computer too.

If I click on > Windows Explorer > My Network Places > Microsoft Windows Network > Workgroup = I get a message that reads:
"Workgroup is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out is you have access permissions.
The list of servers for this workgroup is not currently available."

If I click on ‘Search’ and search for ‘computers’ [My computer is called jen] I get:
Jen in ‘workgroup’.
If I click on jen in the search box I get all the drives and folders on my computer.

My Network places and Workgroup had disappeared from my Start Menu.

Try shutting off your firewall.

If this works you need to open ports for file sharing and server message block (SMB) communications:

Microsoft file sharing SMB: User Datagram Protocol (UDP) ports from 135 to 139 and Transmission Control Protocol (TCP) ports from 135 to 139.

Direct-hosted SMB traffic without a network basic input/output system (NetBIOS): port 445 (TCP and UPD).