right click > arrange by > show desktop icons
if that doesn't do anything you icons have been deleted, check recycle bin
start > my computer > click folders button at the top of the window, look for recycle bin on the left hand side
if you can find your icons there, select them and click restore, if not, then they have been deleted permanently
try system restore: start > all programs > accessories > system tools > system restore
if there's a date available a week ago, try restoring to that point
if that doesn't help you will need to recreate all your icons manually