Do the desktop icons appear? There are 3 problems i can think of.
1. If the desktop icons do not appear, than press CTRL+Alt+Delete, under the Applications tab press "New Task" and type in there "explorer" and press ok.
2. If the desktop icons appear, than:
- move the mouse in the bottom side of the screen (or wherever you used to keep your taskbar), or try on all the margins, and see if it appears. If it does, right click, select Properties, turn off "AutoHide Taskbar"
or
- move the mouse in the bottom side of the screen (or wherever you used to keep your taskbar), or try on all the margins, and see if the mouse cursor changes to a double arrow when you hover. If it does, just drag it towards the center of the screen to make it bigger so it will be visible. Then right click it, and turn on the "Lock the taskbar" so it won't happen again.