Windows 7 “The username or password is incorrect.”

You'll have to figure out which of your 3 accounts has Admin permission, and login to that account and check the permissions of the other 2 accounts. You'll need an Admin account in order to use neemo's fix on the missing 3rd account most likely.

It's also possible you accidentally deleted one of your accounts. You should use Windows Explorer and examine the C:\users\admin_account_name directory. You should have 3 accounts or subdirectories under that admin_account_name directory; including your own user account with the admin_account_name (this could be your name such as "JOHN") along with 2 other directories which would be Default.migrated and Public directories.

Under each of these subdirectories, you should have the Library folders listed for each of your 3 accounts; Documents, Downloads, Music, Pictures, and Videos. If any of those 3 accounts are missing 1 or more or all of these 5 library folders chances are that account is corrupted and that is the account that is scrambled and should be removed from Control Panel-->Manage Other User Accounts. That account may have been accidentally deleted by you or someone else you share your computer with or by a virus.

If any of these other accounts are being used by friends or family members sharing your computer, you should ONLY have Administrator rights on your account, the other 1 or 2 accounts should have Standard rights or Limited rights so if they are logged onto your computer while you are not there, they cannot install programs or delete any programs from your computer without having your Admin password.

If you are the only user on this computer, why are you using extra user accounts?

That should also help you fix it.
<<<BIGBEARJEDI>>>