Installed software / background
Windows 7 32 bit
VS 2010
TFS 2010
Single server / basic installation
No errors on install
Cannot log in to the Team Foundation Server system at all - no combination of user accounts will be accepted

Scenario
I keep getting a TF31003 not authorized error no matter what I use to try to login with.

If I use the service account which is reported as being used in an info screen during the basic install (NT Authority\LocalService) or the administrator account I was logged into when I installed they both give the error.

Cause of the problem
I couldnt add the permissions to my main admin account because I dont have a password on my home computer admin .

Solution
I created a special account for using Team Foundation Server with, added a password then opened a cmd window in the following folder:

C:\Program Files\Microsoft Team Foundation Server 2010\Tools

and executed the following command:

tfsconfig accounts /add /account:"TFSAccount" /accountType:applicationTier /password:yourPassword

TFSAccount is the name of the TFS account I created
your Password is the password

Replace yourAccount with your account name that you created. If you have spaces in your account name you must put speech marks around the account name as demonstrated above. If you are on a domain (such as a corporate network) you might have to enter your domain such as "someDomain\yourUsername". You should be able to figure this out based on the username and password you use to login to windows.

Replace yourPassword with the password you assigned to the account.