I have an excel file, I can open it but its spreadsheets and the whole workbook is password protected, so I can't be able to copy, edit or print it, On addition to that, it is was shared from an unknown network. So it is a shared workbook as it states it on its title bar. Who can help me to unlock this workbook, I don't know the password.

Contact the author.

What do you mean from an unknown network? But Ben is right. If someone placed a password to protect the sheet, then you have no right to get access to the sheet without the owner's permission.