Dual Display Doesn't Work

I have Windows XP Home, Sp. 3 with all updates. The graphics card is an ATI Radeon HD 5800. The motherboard is an MSI 890FXA-GD65. The system is new and works fine in all respects except with dual display.

I am trying to get a dual display set up.

When I boot up, both displays show the MSI splash screen as well as the Windows startup screen. When the main display bootup is complete, the secondary display is dark. When I go to the Catalyst Control Center Display Properties screen and try to do anything in the way of detecting or setting up the type of display I want the entire system locks up and I have to do a hard reboot On one occasion the secondary screen showed a desktop with no taskbar, and on another occasion I could move the mouse back and forth across the two screens, but I am now unable to reproduce either of those.

Your suggestions will be appreciated.