windows display changes can be done under the "display properties" window. Click on an empty area of the desktop->properties->themes or appearance buttons(advanced if needed)
You will need to play with it and/or find what you like. Beware, changes can effect other parts of the display to include the taskbar. From memory, I don't know if you can directly change taskbar, alone though. You can add more "desktop" changes if you use MS windoze Plus! s/w or any other 3rd party themes some free others you pay.
i have seen someone change his start-taskbar background into something like a wallpaper...the default is grey(if thats correct)in xp...how he do that?can someone talent please help me?