Experienced help needed!
If the only thing, (and I mean the ONLY thing) that is affected is the blue title bar for each and every window and/or dialog box or alert message box, then the problem is a gradient setting in the current windows theme.
This would show as a colour change going from left to right on the title bar of the window and when you re-size or move the window the colour change follows the window.
Fix --- right click on desktop background and select display properties. navigate the tabs till you find the current theme. (probably listed as custom theme). Pick Windows classic theme or some similar name from the drop down list.