Asp.net sql hatası bağlantı hatası

Arkadaşlar asp.net de site yapıyorum ve sql bağlantı hatası aldım bi türlü çözemedim.
Hatanın Detayı

System.Data.SqlClient.SqlException was unhandled by user code
HResult=-2146232060
Message=Sunucuyla bağlantı kurulurken ağ ile ilgili veya örneğe özel bir hata oluştu. Sunucu bulunamadı veya sunucuya erişilemiyor. Örnek adının doğru olduğunu ve SQL Server'ın uzak bağlantılara izin verdiğini doğrulayın. (provider: Named Pipes Provider, error: 40 - SQL Server için bağlantı açılamadı)
Source=.Net SqlClient Data Provider
ErrorCode=-2146232060
Class=20
LineNumber=0
Number=2
Server=""
State=0
StackTrace:
konum: System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
konum: System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
konum: System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, Boolean withFailover)
konum: System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, Boolean withFailover)
konum: System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString connectionOptions, SqlCredential credential, TimeoutTimer timeout)
konum: System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance)
konum: System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData)
konum: System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions)
konum: System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions)
konum: System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
konum: System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
konum: System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)
konum: System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)
konum: System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)
konum: System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
konum: System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
konum: System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry)
konum: System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)
konum: System.Data.SqlClient.SqlConnection.Open()
konum: Site.Default.btnKayit_Click(Object sender, EventArgs e) c:\Users\Mete\Documents\Visual Studio 2013\SiteBlog\Site\Site\Default.aspx.cs içinde: satır 26
konum: System.Web.UI.WebControls.Button.OnClick(EventArgs e)
konum: System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument)
konum: System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument)
konum: System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument)
konum: System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData)
konum: System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
InnerException: System.ComponentModel.Win32Exception
HResult=-2147467259
Message=Sistem belirtilen dosyayı bulamıyor
ErrorCode=-2147467259
NativeErrorCode=2
InnerException: