Identifying and solving connectivity problems is a frustrating process. Here are some hints to make your life easier. First, verify that you can connect to your server outside of SQL Server. Try connecting to a drive on the same machine. If you are using TCP/IP, ping the machine and see if there is a response. In this way you will determine if the problem is SQL Server or network connectivity as a whole. Next, determine if the problem is specific to one client by trying to connect from another machine. You should also try switching between different protocols (named pipes, TCP/IP, and so on). In the same way, try both OSQL, which uses ODBC, and ISQL, which uses DBLIB. The more you know about the scope of your problem, the easier it will be to solve it.