Provided the SQL installation is correct, and has been configured to allow network connections (the default), and has no ports blocked on the server firewall, all you need is a valid connection address (which will be of teh form
\\MachineName\\InstanceName).
If you use SSMS to work out the connection, it can scan the local network and tell you which machines have which instances - to connect from your software, you would need to translate that into a valid connection string.
We can't help you do that: we have no access to your network or machines!
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if you are trying to produce an app that will connect to the same DB regardless of the PC it runs on, then this may help:
Instance Storage - A Simple Way to Share Configuration Data among Applications[
^] - I use it so that I can set it up once and not have to worry about it for any other app. If the server PC changes name or login type, I only have to change it once per machine / user (because the login permissions may be different between two machine users).
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