If you install windows, then yes
You can't.
If your laptop has the required processing power, you can play Steam games on your laptop. Both my brother and I play Steam games on our laptops.
There are a wide range of games to play on a Macbook. Visit the Apple's game page for some suggestions. Apple also maintains a download site that includes a game section which features demos of commercial games and shareware/freeware games. You can also play online games at many websites. (See links below) The games are widely available (depending upon where you are) from stores or online retailers such as Amazon.
NO but if you use bootcamp you can play it on Vista/ XP, or you can use Crossover games
use Windows Bootcamp... it allows you to play Windows games and other stuff
No.
Bootcamp, install windows on your mac.
as many as you want to download they are free to play and Steam will never limit you for free games :) they are awesome like that.
Yes you can.
Popular ways to play free PC games without ads require a game client such as Steam Download the Steam client to download and play free games. There are also PC games available for purchase on Steam.
No.
The best to pay for your steam games is through Paypal. Steam is a gaming platform online that allows you to not only play games but connect with other people as well.