Max connections SQL Server Express could have? I have SQL Server 2005 Express edition installed on one of my client's machine, and lots of other users are also connected to that SQL Server through the C# application that I have provided them as an interface.

Sometimes a pc get connected to SQL Server and sometimes just throw the exception 


  SQL Server not found....


I believe the Express edition reaches the maximum connection limit of it and then gives error.

Please guide me how could I solve this issue.

Any white paper that help me know which edition have how many number of parallel connections,

I am open to upgrade to SQL Server 2008 or SQL Server 2012, but prefer Express edition. I could go for other versions as well if they really pay me back in this context, otherwise Express edition is doing well.
It seems with Windows 7, you can have up to 20 concurrent connections but no more. 

If you need more, you'll have to put your SQL Server installation onto a Windows Server OS. 

Also see this other SO question on the same topic - SQL Server Express does not limit the number of max connections (which have a 32'768 limit on any edition of SQL Server)