Desktop Icons and Taskbar disappeared (Vista)?

I have no clue why but My grandmother used my computer and when she exited out of the internet the desktop icons and taskbar disappeared. Everytime I restart the computer they reappear for like 5 seconds and it's gone again. It shows my desktop background but if I do Ctrl-Alt-Del I click on task manager and then it makes my screen go black and thats it. How can I fix it? I'm on my laptop atm