Connection only showing tiny squares like Windows mouse trail.....

Hello,

I have an issue with a remote connection to a Win7 laptop which works absolutely fine 80% of the time but every so often it has a wobbly where it displays a black screen. When you double click the mouse a small square (a 100th of the screen size) displays of the connection image and when you move the mouse about this 'tiny square' follows like the Windows mouse pointer trail leaving squares of image all over the screen.

So if you start on the left of the screen and move the mouse quickly to the right you will get 10-15 'tiny squares' of the image on the black screen but the image in each square isn't of the connection image behind it - but probably just a few pixels from where you started.

If you move the mouse very slowly in small areas or patches then you can build up the connection image behind that area of the black screen. After finding the 'password' input box and logging in the tiny square displays images of the deskptop.

I have played about with resolution and quality settings without luck and also done a remote restart. Apart from the black screen & tiny square the connection seems to work - file transfer is ok. Screenshots;

MOVING ACROSS THE SCREEN

BUILDING UP A PATCH OF IMAGE 

FOUND PASSWORD BOX TO ENTER PW & LOGIN 

Has anyone experienced this and was there a remote fix to get it working correctly?

Thanks.