In order to allow workstations to connect to SQL Server on your main/server computer, Windows Firewall exceptions will need to be added. Complete the follow steps on your main/server computer.
Open Windows Firewall panel.
Windows 7 users: Click Start, Control Panel.
Windows 8/10 users: Cliek the Windows start button and start typing "control" click "Control Panel' in the search results.
Inside of Control Panel, in the upper right hand corner, change to View by Small icons. Then choose Windows Firewall.
Click on "Allow an app or feature through Window Firewall" on the left hand side menu.
Click on "Change Settings" in the upper right and then click on "Allow another app" button to choose your files.
Click the "Browse" button next to the "Path" field and browse for the first file:
C:\Program Files\Microsoft SQL Server\SQL Instance Name\MSSQL\Binn\sqlservr.exe
Click on sqlservr.exe file and then click "Open". Click "Add".
Click "Allow another app" and click "Browse" for the second file
32 bit computers (without a Program Files(x86)) folder:C:\Program Files\Microsoft SQL Server\90\Shared\sqlbrowser.exe
64 bit computers (with a Program Files(x86)) folder: C:\Program Files (x86)\Microsoft SQL Server\90\Shared\sqlbrowser.exe
Click on the sqlbrowser.exe file and click "Open". Click "Add".
Close out of the Firewall exception panel and then close the Control Panel. These entries should allow your networked workstations to connect to your SQL Server. if you use any other antivirus or third party firewalls, you will need to add the same exceptions to that software as well.