SiS M650 monitor help on Dell Laptop

Recommended by Wim's BIOS...

hi, please tell me someone can help me, i'm using a dell laptop and one day my computer decided to recognise a second monitor in display properties that doesn't exist and doesn't show anywhere else on my computer. Can anyone tell me how to get rid of it as it now affects when i open software that requries full screen, mainly games. It opens games in 800x600 while my screen is in 1024x768 and no it doesn't help if i change my screen resolution to 800x600. i still end up with a small screen inside a black frame.

Please help if you can as this is really starting to annoy me.

thanx
Ellie