Windows 8.1: An Update to Windows 8

Start Button is back 

• Start icon is fixed to the lower left corner of the screen
• Unfortunately, can't disable it :(
• Modern Start Screen, not a old fly-out menu
• Additional options for personalizing start menu
• The big change is the addition of so-called Motion Accents -- live backgrounds that move as you scroll through tiles.

Lock Screen Customization

• In addition to these slide show on lock screen with photos coming from local drive and Sky drive.
• Access to camera directly on lock screen.
• Accepting calls from Skype video and voice calls from lock screen
• Additional Start Tile size

Windowing and multitasking 

• Snapping of windows depends on screen resolution

New look of Search with effective results

An Awesome on screen keyboard

• word suggestions
• easy shortcuts
• word highlight
• Function pop up for special symbols

Sky Drive Integration

Updated store apps, XBOX, music and radio

Tools for photo viewer

panorama capture feature for camera