aha ya i got that "virus" "malware" what ever you want to call it......but lucky i found a exploit with it to hide the display and gain access to the computer, (This was done on a Win 7 Ultimate 64bit) So hit Ctrl-Alt-Del hit shutdown then it should go back to desktop and it will say something along the lines, "Windows is shutting down, closing background programs." then hit cancel as soon as that shows up, if it does not and just shutsdown then boot back up and as soon as your on the desktop open as many programs as you can then the "virus" should come up, then try again. If this does not work I'm sorry i cant help further, well i can but I'm done now so....bye.
edit: Oops almost forgot when the "wall" hiding your desktop is gone get some kind of anti-virus and run "full" scans, I got 4 of them and its gone now. I used Hijack-This, Malwarebytes, Spyhunter, and HitmanPro. So you can try any/all of them if you want too......i mean i can't stop you......can i?......no i cant....