I just installed SQL Server 2008 CTP (Katmai) and all the patches on my Vista laptop…  However, trying to login using SQL Management Studio or osql using integrated security (and, yes, I’m an admin on my box) results in the “login failed” error.

To resolve the problem, I had to turn off the “User Control Account” and reboot.  Now, I can login to SQL without any problems… 

If you do want to enable User Control Account feature in Vista, simply add your Windows login to SQL Logins…