if it's windows XP, 2000, or ME then right-click on the blank select 'Arrange
Icons By' and select 'Show Desktop Icons'
as for the Taskbar it could be hidden, drag your mouse to the bottom of the
screen and if it appears right-click on it select 'Properties' and uncheck
'Auto-hide the taskbar'
you may need to reboot your computer to Safe mode and and select System
Restore to undo the chabges, as a last resort...(if you know how)