Windows Key – Simply pressing the Windows key will bring up the Start Menu with its mix of Windows 7 and Windows 8 styles. You can just start typing the name of an application or Store app or computer setting and then press Enter to open it.
Windows Key + D – Missing the desktop? This hotkey will hide all windows and show you the desktop. If you press it again, it will bring back the same windows that were active earlier.
Windows Key + L – This hotkey will lock the screen in Windows 10. You could also press CTRL + ALT + DEL and then press Enter to lock the screen, but this is also a good option.
Windows Key + E – Opens Windows Explorer. You can also configure the default folder for Explorer to open to This PC or Quick Access.
Windows Key + R – Brings up the Run dialog box, which lets you quickly run commands. Also, it’s easy to open the command prompt by using this shortcut by simply typing in CMD.
Windows Key + Tab – This will show you a thumbnail of all open programs on the current desktop and also a small thumbnail of each desktop at the bottom. You can use the arrow keys to select a different program on the active desktop.
Windows Key + I – Opens the Windows 10 Settings dialog where you can configure the network, backups, WiFi, privacy, security and lots more.
CTRL + Windows Key + L/R Arrow – This allows to switch between desktops quickly using the right or left arrows in conjunction with CTRL + Windows Key. The order for the first two keys doesn’t matter either.
Ctrl + Shift + Esc – This will bring up the new Windows 10 Task Manager. The shortcut is the same as it was in previous versions of Windows.
Windows Key + C – This will bring up Cortana in listening mode, if you have Cortana enabled. If you use it, this is a handy shortcut.Source : TechTips