Hi Ethannat,
This issue may occur due to incorrect user account settings or if the User profile is damaged. Let's try few steps to resolve the issue.
Method 1:
I would suggest you to open User Accounts Window and click on Manage another account. Check if you have any other accounts on the computer or if there are any options to create another accounts.
Refer to the article: http://answers.microsoft.com/en-us/windows/wiki/windows8\_1\_pr-security/manage-another-account-windows-81/a8ce0876-5098-4bcb-b459-4328109b60cc
Method 2:
If the issue persists, I would suggest you to boot the computer to Safe Mode and check if you can login to any administrator account and create a new account from there.
Windows Startup Settings (including safe mode)
http://windows.microsoft.com/en-IN/windows-8/windows-startup-settings-including-safe-mode
Create a user account
http://windows.microsoft.com/en-us/windows/create-user-account#create-user-account=windows-8
Additionally please provide the screenshots of Manage another user accounts Window to understand the issue better.
How to include a screenshot in your post
Hope this information helps. Reply to the post with updated status of the issue to assist you further.