Cannot log in with any account

[Zuassi]

Cannot log in my forum with any account. Cannot register too because it doesnt show capatcha. When trying to log in it says "write your username", nobody can log in forun now. If need more info please ask

[Zuassi]

Still in trouble..

[JimM]

You didn't provide a link.  Did this start to happen after adding a mod?  Are you suing the default theme?

How do I ask support questions the smart way?