Keychain Access

Hi, I have recently got my new Mac mini. When I turned it this morning it stated Mac OS X wants to use the "login" keychain. Please enter the keychain password. But it will not accept any of my passwords to unlock it. It will not me open keychain access from the utilities menu to carry out the suggested solution in the support forum. How do I reset the password? Or how else can I move forward with this issue. It will not me open safari or mail but has downloaded my iPhoto's

Thanks