Microsoft Windows 7 Ultimate, Full Version (PC DVD) £165
Windows 7 Ultimate is the most versatile and powerful edition of Windows 7. It combines remarkable ease-of-use with the entertainment features of Home Premium and the business capabilities of Professional, including the ability to run many Windows XP productivity programs in Windows XP Mode. For added security, you can encrypt your data with BitLocker and BitLocker To Go. And for extra flexibility, you can work in any of 35 languages. £165.58 from Amazon.