Q: Airplay won't work!!

About AirPlay and Airplay Mirroring

AirPlay Mirroring requires a second-generation Apple TV or later, and is supported on the following Mac models: iMac (Mid 2011 or newer), Mac mini (Mid 2011 or newer), MacBook Air (Mid 2011 or newer), and MacBook Pro (Early 2011 or newer). For non-qualifying Macs you can try using Air Parrot.

Several Apple Articles Regarding AirPlay

Apple TV (2nd and 3rd gen)- How to use AirPlay Mirroring

How to set up and configure AirPort Express for AirPlay and iTunes

iTunes- Troubleshooting AirPlay and AirPlay Mirroring

iTunes- Using AirPlay

Apple TV (2nd and 3rd gen)- Understanding AirPlay settings

About AirPlay Mirroring in OS X Mountain Lion

iTunes 10- About playing music with AirPlay

Troubleshooting AirPlay and AirPlay Mirroring

Using AirPlay

Thanks to the $15 Beamer, AirPlay streaming is still possible on Macs  that do not support Airplay and mirroring.

Other solutions are the Air Parrot, StreamToMe, and AirServer.

If you have a MacBook, not a MacBook Pro, then it does not matter. You cannot use Airplay on a MacBook. If you have a MacBook Pro then open About This Mac from the Apple menu and click on the More Info button. At the top you should see a description of your model.

Couldn't tell you. I don't use it. See if any of the links I provided help you in some way.