To get your desktop folder view back; Right click on the desktop, "Add Widgets", search for folder, double click on the folder. It will open as your "home" folder. Right click on it and select "Folder view settings" and then select "Show the desktop folder" in "Location". To get your panel back; Right click on the desktop and select "add panel -> default panel" You can then add the system panel from "add widgets".
If it stays corrupt, make a back up of /home/username/.kde4 and then delete it and reboot.
Self-righteousness is a loud din raised to drown the voice of guilt within us - Eric Hoffer
Don't believe what it says on the right - I am anything but sagely; More oniony!