mssql_connect() no longer works with PHP 5.3 and up. As of PHP 5.3.2 you have to use the SQLSRV API functions to connect to an MS SQL Server database from PHP. For example, use sqlsrv_connect() to create a connection resource and open a connection.
If you forgot your Umbraco admin password, use the following SQL query to reset your Umbraco admin password in SQL Server Management Studio (SSMS) or MySQL