You could go into your home directory and remove the .kde
folder and any other .kde folders you may see and the Desktop
folder and then logout and log back in you will be back at a default desktop, might have to go through the kde wizard again but everything should be back.
In the file manager you may have to check the view hidden files
if using konqueror if it is going to nautilus you will have to go into edit -->preferences-->show hidden files
or if you are in a command line ls -ali | grep kde
and remove the .kde that shows up all within your users home directory.