Sorry, oops!

I created the link but just forgot to add it to my post.

How to change text and background color in Windows 10

Read the whole page because he explains why it is a roundabout process, having to change the theme to a high contrast theme and then that allows you to modify what you want. All the things you could do easily in older versions of Windows but which are inaccessible in Windows 10. Then he suggests an alternative, which is to create a theme in Windows 7, then share it so that you can transfer it to the Windows 10 computer.

Microsoft has created a complicated process for what used to be simple & easy and then smart cookies like the guy on that site have to think up what we call "workarounds" at my work, which are convoluted processes to achieve something which should be simple but the system won't let it happen. I don't get it. It's just annoying.

Try those instructions and see whether it solves the problem. If not, there is always plan B, and C and XYZ.

Helen