Vicki,
Ok, there are two possibilities that I can think of that might be causing your problem.
1. I’m running Win 8.1 Pro if you have 8.1 Standard it may not allow you to hide updates.
You can check your OS version via File Explorer -> Right-Click on Computer (in left hand pane) -> Select Properties
41312-Win81pro
2. I’m running an Administrator account if you are using a Standard User account this could also possibly preclude you being able to hide updates.HTH :cheers:
I have a Standard account and have had no problems hiding updates,off out now but will have another look in a few hours.