Win+Shift+M - Reverses the previous action (Win+M)
Win+D - Shows the Desktop
Win+↑ - Maximize the current window
Win+↓ - Restore the current window
Win+← - Putting the current windows on the left half of the screen
Win+→ - Putting the current window on the right half of the screen
Win+↑ - Increases the vertical side windows on the highest value
Win+↓ - Sets the vertical sides of the window to the previous value
Win+Space - Shows Desktop (same function like "Show desktop") works only if your PC support Aero themes.
Win+Home - Minimize/Maximize current window
Alt+F4 - Closes the current window
Alt+Tab - Return window that was previously active, if you hold Alt and press Tab more times you can move cyclically through all open windows
Alt+Esc - Alternately shows every open window
Win+Tab - Display all open windows in 3D, if you hold Alt and press Tab more times you can cyclically move throught all open windows with a very beautiful 3D animation
Ctrl+Win+Tab - Similar to the previous shortcut, except that now the windows remain in 3D until you select the window
Shorcut Keys for Taskbar:
Win+Some number - Open app that is pinned on taskbar under that ordinal number
Win+T - Cyclically moving through the applications in the taskbar
Win+Shift+T - Same action as the previous shortcut but in the opposite order
General Shortcut Keys:
Win+P - Shows options that allow the display images on two monitors
Win+G - Shows active Gadgets on Desktop
Win+L - Lock your account, same action like "Switch user"
Win+ + - Zoom in
Win+ - - Zoom out
Win+ = - This shortcut starts magnifier
Win+R - Starts RUN → by compfixing
Win+E - Starts My Computer → by compfixing
Ctrl+C - Copy → by compfixing
Ctrl+A - Select All → by compfixing
Ctrl+V - Paste → by compfixing
Ctrl+X - Cut → by compfixing
F5 - Refresh Desktop icons → by compfixing
Shrotcut Keys for Web Browser :
Home - Scroll up
End - Scroll down
Ctrl+U - View page source code
Ctrl+N - New tab
Ctrl+W - Delete current tab
Ctrl+H - History
Ctrl+F - Search
F5 - Refresh Web page
F11 - Full Screen
F12 - Inspect element
Shortcut Keys for Windows Explorer:
Alt+P - Show/Hide panel for displaying marked file
Alt+↑ - Switches to one level above the current folder
Alt+←/→ - Returns to the previous folder or go to the next folder