Can't Close It

Open any application the victim might normally have open. Press "PrtScn" to capture the desktop as an image (make sure the mouse pointer and task bar can not be seen). Next, open an image editing program, and paste the image. Then save the images as a file. Next, right click on the desktop, select "properties", and browse for the image you just created. Select that image as your background (make sure that it is stretched and not centered or tiled). Your victim will think he has the application open on his computer and won't understand why he can not close it or minimize it.