My ISP Provider (Cox Communications) is blocking SQL Ports. This issue is transparent to the most of residential internet users. In my case it has caused me much grief and wasted time. Thankfully, I was able to find a solution (without upgrading to a Business Plan, which in my case was nearly $60 more per month – no bueno).
Here is the scoop.
If you try to connect to a remote sql database using just the following as a server name: IP Address\SqlExpress , there will be a nasty error (see below). In my case this was a sign of ISP Blocking SQL Ports. 
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: SQL Network Interfaces, error: 26 – Error Locating Server/Instance Specified)
Note: Remote server does allow remote connections because all of my coworkers not using the same ISP provider connected to that server remotely just fine.
So here is the solution (it is rather simple, if you can access ERRORLOG file on the server).
On the remote server, navigate to the following location:
C:\Program Files\Microsoft SQL Server\MSSQL10_50.SQLEXPRESS\MSSQL\Log
There should be an ERRORLOG file (there could be several, but look for the one that has the latest date stamp). In that ERRORLOG file, see if you can find something similar to this:
2011-09-30 13:49:21.07 Server Server is listening on [ 'any'
2011-09-30 13:49:21.07 Server Server is listening on [ 'any'
Number 49910 is a port number that will have to be appended to the server name (it will most likely be different on each server).
In my case, here is the connection string that worked:
IP Address\SqlExpress, 49910
Hopefully, this helps someone.
This year I have attended another online conference – 
