Windows Basic Keyboard Shortcuts, this list is no where near complete and this is just a simple list

Copy

Ctrl + C

Cut

Ctrl + X

Paste

Ctrl + V

Print

Ctrl + P

Save

Ctrl + S

App Switcher

Alt + Tab
Continue to hold down Alt to keep switcher menu open

Show Desktop

Windows Key + D

Open Start Menu

Windows Key or Ctrl + ESC

Open Task Manager

Ctrl + Shift + ESC or Ctrl + Alt + Delete

Text Formatting

Bold

Ctrl + B

Italics

Ctrl + I

Underline

Ctrl + U

New Document

Ctrl + N

Open Document or File

Ctrl + O

Web Browsers

New Window

Ctrl + N

New Tab

Ctrl + T

Re-open Last Closed Tab

Ctrl + Shift + T

Close Tab

Ctrl + W

Navigate Back in History

Backspace or Alt + Left Arrow

Navigate Forward in History

Alt + Right Arrow

Full Screen View

F11

Windows 7/8

Open Start Menu

Windows Key or Ctrl + ESC

Show Desktop

Windows Key + D

Open Run Prompt

Windows Key + R

Open Pinned Application on Taskbar

Windows Key + [1-9]
Where 1 – 9 will open the application in that position on the taskbar.

Open Windows Explorer

Windows Key + E

Open Windows Search

Windows Key + F

Lock Computer

Windows Key + L

Open System Properties

Windows Key + Pause/Break

Minimized All Windows

Windows Key + M

Un-minimized All Windows

Windows Key + Shift + M

Application Switcher

Windows Key + Tab
Switches Metro or Windows Apps

Select items on the Taskbar

Windows Key + T

More shortcuts are coming soon, feel free to share your favorite ones in the comments.

Sources: Wikipedia: Windows Key