1) Take a screencap of your desktop.
2) To cap a desktop:
For PC: Press "Print Screen" (prt sc) button.
For Macs: Shift+Apple+3.
3) Open your graphics program-o-choice.
4) Press CTRL + V or go to "edit & paste.
5) Save image as a JPEG.
6) Upload the screen cap to your image server.
7) Post your cap in YOUR LJ along with these instructions.