KDE 4.9.5 - White Blocks appearing on screen

[tcc]

Hi,

I am new to the KDE desktop.
I am experienceing this reall annoying problem with my desktop:
When even I do something with a window, virtual desktop etc.... I get white blocks appearing on the top edge of elements, it seems.

I have included an image below.

This happens when I change workspace, open/close a window, sometimes when I open the Kickoff menu!

I am running on an Intel i5 (Sandybridge) laptop, with HD4000 graphics

http://i.imgur.com/HX3YJU4.png

Any help greatly appreciated

Tcc

[KilUma]

Best guess, you're default resolution is 1366x768, which your hardware manufacturer warns against using anything different due to hardware rendering(you don't want to burn up your GPU). Start by verifying your resolution settings. Your resolution must be set at 1366x768. Then, Set your color depth to max(usually 24bit).

However, if your system is built with the NVidia Graphics card(some of the younger Dell systems are), then that is a different topic- which is beyond my expertise.