You will find your Mac's serial number by selecting About This Mac from the Apple menubar.
If you have a non-working Mac you'll find the serial number printed on the case:
MacBook/Pro/Air; Mac Minis - bottom case by the regulatory markings. iMac (all models) - underneath the stand. Mac Pro family - back of the case (2006-2012 models); bottom of the case (2013 models).
FREE Technical Support:
- Contact us if you need help with troubleshooting a Mac problem or with installation of a replacement Apple part: FREE Tech Support
- We have access to thousands of Apple parts but only those in high demand are listed on our site. If you need a specific Apple part that isn't listed here please contact us, we almost certainly will have it available at a reasonable price: Mac Parts Request