Select CLONE, Y not spanned desktop. Clone and Span modes tell Windows that only one monitor is present on the machine. They don't give Windows control over individual monitors, but they don't require Windows to support multiple monitors either.

True Multi-monitor mode is different. Here, the display driver tells Windows the actual number of monitors attached to the computer. Each monitor can have its own display and each can have its own independent display resolution and color depth.

Does your computer have True Multi-monitor support? One way to tell is to right-click the Windows desktop and choose Properties from the popup menu then click the Settings tab of the Display Properties dialog box.
You MUST have latest drivers from manufacturers web site installed to. Us the control panel from that to adjust.