System Restore might revert things back to how they were before.
To change the look of Window elements (From Help and Support)
Open Display in Control Panel.
On the Appearance tab, click Advanced.
In the Item list, click the element you want to change, such as Window, Menu, or Scrollbar, and then adjust the appropriate settings, such as color, font, or font size.
Click OK or Apply to save your changes.
To open Display, click Start, point to Settings, click Control Panel, and then double-click Display.
Your changes are saved until you make further changes or choose a different theme.
Changing the look of individual items is only useful if you select Windows Classic in the Windows and buttons list on the Appearance tab. If you select a different option, the theme determines the appearance of your menus, fonts, icons, and other Window elements.
The Font area will be unavailable for elements in the Item list that do not display text.