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.
On my wife’s machine the desktop is also affected (horizontal bands of faded rainbow colors) and there is a series of graphics with very complex designs that show up only on the startup screen, in the upper left corner.
The first one to display was a drawing of a gear with a splined center and bevel-cut teeth around the outer circumference, like someone’s high school drafting project.