ThinkPad Yoga with Windows 8.1
Windows 8 Laptops and All-in-One PCs
Windows 8:
Beautiful, Fast, Fluid
Microsoft's sleekest, most innovative operating system yet. Built around touch technology and tiled applications, the OS takes the PC experience to a new level of customization, consumption, and creation.

Created specifically for the new Windows 8 OS, Lenovo has combined the best hardware and software features to create Lenovo Enhanced Experience 8.
ThinkPad Helix Windows 8.1
Windows 8.1:
Advancing the Vision
Windows 8.1 delivers the experiences that customers need and expect in the next generation of PCs, tablets, and other devices, for both individual consumers and businesses. It's Windows 8 but even better.

Your Personal Experience Across Devices

Use your Microsoft account  (email address / password) to sign in to Windows 8.1 and instantly connect to great services across all of your devices. Personal settings like your lock screen and Start screen follow you to other Windows 8.1 devices. Your favorite websites, browser history, and pinned sites on your Start screen move with you, as well. With a Microsoft account, you can access your stuff from virtually anywhere using a browser or the SkyDrive app. Your Calendar, Mail, and People apps are connected via your Microsoft account, so you can stay in touch and up to date at all times. Skype, Xbox, Outlook.com, and Windows Phone use your Microsoft account, as well, so your services and devices are connected with a single user name and password.

And, of course, your Microsoft account also gives you access to all the apps in the Windows Store. Download the apps you've purchased to any PC or tablet at home or at work, as long as it shares the same Microsoft account.