If you're just using the XP supplied drivers, they may not support dual monitors. Make sure you're running the latest drivers from ATI.
For that matter, make sure your video card is equipped to do dual monitor, because not all of them are.
I have dell dimension 8300 running windows xp home addition .My video card is a radeon 9800.when I go to
display/ settings ,there is only one monitor displayed.
on my old computer there was always a picture of 2 monitors 1 as primary and one as secondary ,you could then pick to spread your desk top over both monitors
any ideas how to get- settings- to display icons for 2 monitors?so I can setup my double desk top ?is there a way to activate my second screen icon in settings?