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.
HTH