Colors will not show on screen?

Dear All,

I have a strange problem with Excel. Colored fonts, fills and borders will not show on screen, even though I know how to do this. All text remains black and cells remain white. My screen is OK, because colors & fills show up OK in other applications (such as Word), and they also show OK in "print preview" mode, and also when I print. It's only on the main Excel screen that the colors do not appear. Opening the same file in another computer shows up the colors fine. Is there some obscure Excel setting that is causing this behaviour? What do you think?

Many thanks everyone ...

Dear JR,

I will try that solution. The problem is on a friend's computer, so I can't try it now. But I'll post a comment when I do give it a go to let you know. You'd think if it was a general setting, then it'd affect other applications, and the "print preview" in the same application, wouldn't you?

Thanks

Dear JR,
Thanks again, your solution worked. Some game or download or teenager must have changed the High Contrast setting. Unchecking it restored all colors on the Excel page.

Thanks again for your assistance.