Surely you've considered the possibility that this is malicious code (virus, worm, Trojan)? You ought to do some testing to find out what it is. Have you run at list two different brands of anti-virus software (with current updates) to see if this is malicious code? What OS are you running? Is this thing really a window (with a frame / title bar)? Describe it more precisely for us. If you're able to move it, is that done by placing the cursor over some part of it and dragging it, or by some other method (like with the keyboard)? If you're running Win9X or ME, look at your Close Programs list to see if there's a process listed there that you do not recognize. If you're running WinNT or W2K, look at your Task Manager to see if there's an unknown process listed. You might also want to check
this URL to see if a search for the characteristics of this "window" turns up anything. Get back to us with your findings. Good luck.
Regards,
Jim