I recently moved my app to a new server - the app is written in c# against the 3.5 framework. The hardware is faster but the OS is the same (Win Server 2003). No new software is running. On the prior hardware the app would run for months with no problems. Now, in this new install, I get the following error after about 3 days, and the only way to fix it is to reboot:

A network-related or instance-specific error occurred while establishing 
a connection to SQL Server. The server was not found or was not accessible. 
Verify that the instance name is correct and that SQL Server is configured 
to allow remote connections. (provider: TCP Provider, error: 0 - An operation 
on a socket could not be performed because the system lacked sufficient buffer 
space or because a queue was full.)

I have yet to find a service I can even shut down to make it work.

Anyone had this before and know a solution?