Hi Rita_Robbins,
Thank you for reaching out to Microsoft Community.
In turning on the backlight of your keyboard, please make sure first that the Fn key is OFF (not lit up).
Please check then if the F7 key on your keyboard has a half sun icon or Prtscrn. If it is the sun icon, try to press it several times and check if the keyboard backlight lit up.
If the F7 key is for Prtscrn, please use then the F1 and F2 keys to adjust the keyboard backlight.
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Kind Regards,
Marrion Y.