How cool is that?
Downsides: WinXP only. A myriad of dependencies you're not likely to have installed on your machine (.Net Framework 2, Windows Installer 3). The latter dependecy requires Genuine Windows Validation, "hmm what's that?" I wondered.
Oh! You have to actually have a legally licensed version of WindowsXP and be able to prove it for the install to work.
Does it matter if your copy of Windows is genuine? Yes, if you want the confidence of knowing that your software is legitimate and fully supported. And only genuine Windows customers can receive product downloads, Windows updates and special offers.