Hi

I recently purchased a computer in Sep 2012. with an Intel i5 3570k processor (not over clocked) which has no additional graphics card and runs using the on board graphics HD 4000. I am sure there  is nothing wrong with the monitor or connection to the desktop pc. and the lines of red dots didn't appear immediately when I first had the pc. I wondered if they began to appear once I started updating my pc with the latest windows 7 updates (x64 bit). 

The red dots appear each time I switch on the pc at the very bottom edge of the screen then when the Asus screen appears (motherboard is Asus p8z77-V LX) across the middle of the screen, then again when the windows  start up screen appears and then again if have an image in the centre of the screen which is a dark block. The line of dots only appears horizontally and in red on dark screens. Occasionally I have seen the same lines of dots on a light coloured block in the centre of the screen when the dots are pale blue.

Any advice on how to remove these dots would be gratefully appreciated.

Many thanks

Richard