First, why is modern software still being shipped with this? I found this problem when working with The Digital Office (TDO).

I had a couple computers that wouldn’t connect to the SQL server. The program is Access based and running on MSDE 2000.

click Start, Run, svrnetcn.exe
This will show you what type of connects it is accepting, Named Pipes and or TCP/IP. You can then find the TCP/IP Port.

32 Bit Windows click Start, Run, cliconfg.exe
64 Bit Windows click start, run, c:\windows\syswow64\cliconfg.exe

This will allow you to pick which protocols are enabled. Then you add an alias for the connection. Use the Servername\instance and then set TCP/IP and then set the Port. Icli