The accounts also have to have passwords.Originally posted by: amdfanboy
You have to enable the allow people to connect to this computer option.
Originally posted by: LeetestUnleet
FYI, you're getting that error because the account you're trying to use to login to computer b is not an adminstrator account. There are two ways around this:
1.) Make it an administrator account through Manage->User Accounts
2.) Add the username to the allowed users through My computer->Properties->Remote->Select Remote Users