Dell OptiPlex 755 - Manual (Page 41)

3. Select Change Intel ME Password. Press <Enter>. Type the new password twice for verification.
The new password must include the following elements:
l Eight characters
l One uppercase letter
l One lowercase letter
l A number
l A special (nonalphanumeric) character, such as !, $, or ; excluding the :, ", and , characters.)
The underscore ( _ ) and spacebar are valid password characters but do NOT add to the password complexity.
Change the password to establish Intel AMT ownership. The computer then goes from the factory-default state to the setup state.
4. Select Intel ME Configuration. Press <Enter>.
ME Platform Configuration allows you to configure ME features such as power options, firmware update capabilities, and so on.