Ctrl+Alt+Del
If that doesn't take you straight to the desktop then click on a program and click switch to.
If your on vista, Ctrl+Alt+Esc
Also, if you can press the windows button, the start bar comes up right? Next to that should be a button that takes you straight to the desktop. If there isn't, then right click on the bar at the bottom of the page, click properties, and check the box saying Show quick launch then it should come up.