I am trying to log onto a Mac Mini I haven't used in awhile and I forgot the password. I am trying to reset the password with my apple ID but the computer keeps saying the Apple ID and the password are incorrect whenever I know they are.

If the user account is associated with an Apple ID, and you know the Apple ID password, then maybe theApple ID can be used to reset your user account password.

Otherwise, boot into Recovery by holding down the key combination command-R at startup. Release the keys when you see a gray screen with a spinning dial.

When the OS X Utilities screen appears, select

Utilities ▹ Terminal

from the menu bar.

In the Terminal window, type this:

resetpassword

That's one word with no spaces. Then press return. A Reset Password window opens.

Select your boot volume if not already selected.

Select your username from the menu labeled Select the user account if not already selected.

Follow the prompts to reset the password. It's safest to choose a password that includes only the characters a-z, A-Z, and 0-9.

Select

 ▹ Restart

from the menu bar.

You should now be able to log in with the new password, but your Keychain will be reset (empty.) If you've forgotten the Keychain password (which is ordinarily the same as your login password), there's no way to recover it.