I got locked out of this game - sort of. I can't sign into Windows Live, and you have to in order to save your progress, stats, etc. I can sign into Windows Live just fine outside the game. I tried changing the password. I entered my old to see what it'd say and it told me the new password must be different from the old one. Yet Games for Windows Live tells me that password is incorrect!
Are you SURE that you're not just overlooking something? Games for Windows Live, in my honest experience, has been nothing but super-stable and ultra-reliable.
Of course, I kid. Because of GFWLose, I need to spend 15 minutes getting Dirt 2 to work on the GPU benchmarking rig each time I restore the Acronis image. It's too bad that the Dirt series is definitive for benchmarking, else I'd not even consider using it.
I don't get the reliance on GFWL at all... there's
no reason to make it a win/lose thing like that. In Test Drive Unlimited 2, it requires you to be online for the most part, but if the server is down, or you lose Internet, you can still play offline on the "online" account. Dirt 3 should have been designed the same way.
You may want to re-install GFWL with the installer inside of the Dirt 3 folder, and see if that helps. It's super strange that you can log into the client fine but not the game, though. Did you install a new firewall or anything like that?