desktop disapears!

When i boot up my laptop i get an error box that says:

Desktop
could not load or run C:\users\owner\appdata\local\temp\pmkjj.exe specified in the registry. Make surethe file exists on your computer or remove the referance to it in the registry.

When i close the error box my desktop icons and sidebar disapear completely and i cannot get them back. I then have to reboot again. If i leave the error box allone evrything stays where it belongs. What should i do?