I came across this error when I tried to Install MS SQL 2005 on Vista.I have installed SQL plenty of times and never had problems before on my XP.

My Problem :

The SQL 2005 did install correctly on my 64bit Vista but I was not able to log on to the server and it gave the following error

Login failed for user ‘PC-Name\UserName’. (.Net SqlClient Data Provider)

Error Number: 18456 – Severity: 14 – State: 1