A search of the Nv4_disp problem had revealled that it was something to do with the graphics card/drivers for NVidia Geforce4 MX 440, but since I cleared that up awhile ago this new problem occured.
I use AVG Free, Adaware personal, Spybot and Zonealarm Free and all these show my system to be clean.
I've tried adjusting some of the settings, including lowering the acceleraion setting but I am at a loss.