minimize everything else down, until you are back at the desktop
Click the key that says "print screen or Prt Scr it should be above the Insert key which is on the keypad above the arrow keys.
Open up a program like paint or photoshop
Click edit, paste
Then you want to save it.
Upload it to a site like photobucket (or you can email it to me if you want, I can put it in my photobucket account)
Then copy the URL to the pick, and post it like you would a normal picture.