Cannot create database in Visual Studio

Question

I have an application on Visual Studio 2010, Visual c#. I have created a database for the application and it used to ran just fine. But today when I ran my application, the database wasn't working. I deleted the .mdf file and tried to create a new one, but a get this error

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 connection.(provider:SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)

I don't know what to do in order to be able to create a database again, since I don't know that happened in the first place to disable it.

Answer 1

A few things I can think of...

1. Is SQL Server installed/up and running ?

2. Do you already have a non-user instance database named the same thing in SQL Server?

3. Is your connection string set up properly?