phones changed its password

[Jjudd395]

hi, my cousins Iphone 4 has recently turned itself off and back on again but some how the password has changed and she can't get back on to Her phone, please help.

 

[J. A.]

Welcome to iPhoneForums, Jjudd395!

Is there a message visible as well, or is the iPhone just asking for a different passcode/password?
Did the iPhone belong to somebody else before she got it? Maybe it's still connected to the previous owner's iCloud ID.