Display Properties> Appearance> Advanced
On the Advanced Appearance page, what color is shown as the background
color in the "active window"? If black, double click the graphic in that
area. This will change the text in the "Item:" box to "Window" (or you
could select "Window" using the Items drop down list). Next use the arrow
by "Color 1" to switch to white. Click OK.
Launch Wordpad to check the background color.
NOTE: All applications that pick up their background color from this
setting will display using white.