Ok....old fart is curious....

[junk2drive]

2. Yes, it is recommended that you burn a copy and write the serial number on the CD.

You download a zip that contains an exe file that is the installer. You get a serial number that is required for the install to run. You can also install it on a second computer, like your laptop, but you cannot play two installs against each other.
For $10 more, you can download the game and play right away while you wait for a boxed copy with a printed manual.