With effect from 31 Oct 2014, Micro$oft stopped providing retail versions of Windows 7 & Windows 8. The only 'high street' Windows OS version now being sold is Windows 8.1. Which at least isn't as horrid as Win8.
Next year will (probably) see Windows 10. There is some speculation that Win8.1 users may be offered this as a free 'upgrade'.....
So it seems that Linux or Win8.1 are your only real options to upgrade from the highly popular WinXP, Espada III.