How to replace a screen protectors for my SLR camera?

I have a Nikon D3100 and I bought a screen protector on amazon last year.So, throughout the year it's had a few hits against hard surfaces, sadly. So I have two huge cracks on my screen protector. I bought a new one but I'm afraid to take it off because I read that someone had cracked their LCD screen… Can someone tell me how to replace it?
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here's a picture of my screen protector.

It is clear that you have not been taking care of your camera.

As a working pro, I have never done to any of my cameras you have been able to do in just a year.

You need to send the camera to Nikon and pay the piper. You really need to treat your camera as a precision tool, NOT a hammer

My oldest dSLR is a Nikon D300, over 5 years old and it does not show any of the damage you seem to have inflicted.

You need to loosen the glue holding the protector to your screen. My favorite glue softener is Goo Gone. Apply it, let it set a few seconds then pry it off gently.