Activation problem on windows vista

Hello,
my laptop is asking me to change my product key for activation. I found my product key on the bottom of my laptop and typed it in, when i pressed next the message was 'The product key you have entered will not work with this edition of Windows Vista. You must either run Windows Vista setup or enter a Windows Vista Ultimate product key.' all i want is for my laptop to actually work, can you help me?

yours sincerely Tony