Re: Buying Dell XPS-15(T510705MY)
You would need to purchase a copy of XP and install it yourself. BE SURE you locate ALL drivers for your hardware before you buy - Dell will not have them, nor will it support XP on this model.
The other alternative is to use Virtual PC (free from Microsoft) to run XP on the system under Windows 7. Note that not all versions of 7 will allow this.