SA user password for software which automatically installs SQL Server 2005
With SQL Server 2005, you have at least a couple of options


run sqlprov.exe as local admin which allows you to add domain
accounts to the sysadmin role
stop SQL Server and start in single user mode with the parameter -m
and use SQLCMD or OSQL to add your domain account to the sysadmin
role (EXEC sp_addsrvrolemember 'MyDatabase\MyNTUserName',
'sysadmin';). You can also create a new SQL Server login and add
it to the sysadmin role from the same SQLCMD prompt.