Dual Monitors

Trying to set up dual monitors on Vostro 200 running on XP home. Graphics Properties gives me single monitor as only option whatever I do. I have downloaded and installed latest driver from Intel for Graphics Accelerator, following instructions for dual monitors says click on Themes and Appearances in Control Manager. This is absent on my computer. Do I need to download (update) some other driver? This computer is never used on-line (and thus has not been updated), its main purpose in life is to run Pro-Tools and all I want to do is extend the desktop across two screens. I am not stupid but I'm no computer techie so would appreciate any help going.