Hi Rudl, it's probably some bug in the video drivers that came pre-installed with the machine.

You should find out what video card you have which you can do by right-clicking on the desktop and picking "Screen resolution" near the bottom then push the "Advanced settings" link, in the dialog that comes up the type of video card you have will be shown in the "Adapter Type" box near the top of the dialog.

You'll then need to go to the manufacturer's web site (either nVidia, ATI/AMD or Intel most likely) and download the most recent video drivers they have for your particular card model and install those.

- Michael