How To Get Rid Of Lines Of Flickering Red Dots Across Monitor

I recently purchased a computer in Sept 2012 from Dino PC in the UK where I live. It has been running very well apart from an irritating red dot problem. My pc has an Intel i5 3570k processor (not over clocked) which has no additional graphics card and runs using the on board graphics HD 4000. I don't play computer games. I have connected my monitor (a Hanns G HG 216D) to another computer to check that my monitor or cables were not at fault and the lines of red dots do not appear.

I have my monitor connected to the pc with a VGA cable but I have also connected my monitor to my pc with 2 different HDMI cables and the red dots still appear. I have also connected my pc to a tv to use as a monitor with a different HDMI cable and the red dots still appear. These red dots didn't appear immediately when I first had the pc. I believe that they began to appear once I started updating my pc with the latest windows 7 updates (x64 bit).

The red dots appear horizontally across the monitor screen each time I switch on the pc at the very bottom edge of the screen (in small columns) then when the Asus screen appears (motherboard is Asus p8z77-V LX) in a single line horizontally across the middle of the screen, then again in a single line horizontally when the windows 7 start up screen appears. They then appear again if I have an image in the centre of the screen which is a dark block.

In this case they are grouped together in a horizontal block about 4 dots high and about 30 dots wide to the centre right of the dark area. 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 right of the screen when the dots are pale blue and in the same formation. If I move the mouse over the red dots when they appear in a centre block of a dark colour the red dots momentarily disappear.