Using keyboard shortcuts can make your life easier, save time and help keep you focused while you are working on a computer. Not having to move the mouse every time you need to perform certain task can eliminate a lot of wasteful time. For example, lets say you need to leave the computer for about 30 minutes. It is good practice to lock your computer when you walk away from it. If you logoff, then all the documents and open programs have to be saved and closed. When you return to the computer, opening all the programs and files can be another long process. Instead of logging off, you can quickly lock the computer by pressing: Windows Logo+L. and all of the files and the programs will still be running when you unlock the computer. Try it out!!!
ALT+F4:
Quit program or close the current window
SHIFT+DELETE:
Delete item permanently (Warning: item may be impossible to recover after using this command)
Windows Logo+L:
Lock the computer (without using CTRL+ALT+DELETE)
CTRL+A: 
Select all
CTRL+C:
Copy
CTRL+X:
Cut
CTRL+V:
Paste
CTRL+Z:
Undo
CTRL+Y:
Redo
CTRL+S:
Save
CTRL+P:
Print
F5:
Refreshes the current window.
Windows Logo:
Start menu
ALT+TAB:
Switch to another running program (hold down the ALT key and then press the TAB key to view the task-switching window)
Windows Logo+D:
Minimizes all open windows and displays the desktop (great key to remember to hide facebook page from the BOSS)
Hold down CTRL key and clicking with a mouse on a file/folder will allow you to select multiple selections.
Hold down SHIFT key will select the range of files/folders