No need for defenestration: it’s an AMD64-based laptop. Just wipe the disk, pop in the Windows DVD, and install!
But, keep the Macintosh System Software CDs in case you need to recover it—the recovery tools only run on System X
Macs are more sophisticated than Windows in that regard. No System Software CDs (CDs?) - there is no CD slot on a MacAir. You simply press the Option key on power-on, then choose restore from a backup over the wi-fi. MacAir's automatically continually back up to external storage so you never lose data. Someday Windows will copy that built-in feature, as they do almost every other feature of Macs.
Uh, no. Apple doesn't make AMD processor computers. This is my MacBook Air's specifications showing the processor is Intel: