How to factory reset my Galaxy S7 from a computer?

Here are the 2 ways to factory reset a galaxy phone from your computer, pick one that’s applicable to you:

i. Factory reset via Android Device Manager
If your son has his Google account signed in, you can try factory reset the phone from the web-based Android Device Manager.

1. Sign in to https://www.google.com/android/devicemanager from your computer browser. Note: Use the same Google account as your son used to sign in to his phone.
2. Select the right device from the drop-down menu in upper left corner.
3. Click Erase.
4. On the Erase all data prompt, click Erase.

ii. Factory reset via Find My Mobile
If your son has his Samsung account signed in, you can try factory reset the phone from the web-based Find My Mobile.

1. Sign in to https://findmymobile.samsung.com/ from your computer browser. Note: Use the same Samsung account as your son used to sign in to his phone.
2. Make sure you select the right device.
3. Click Wipe My Device from the menu on the right.
4. Click Wipe.
5. If you get a prompt to enter your Samsung account password, enter it to start erasing your data.

If for some reason, the above methods don’t work on your phone, try hard reset.
http://webcazine.com/17372/qa-galaxy-s7-edge-how-to-hard-resetfactory-default-reset-my-phone/

And the screen is defekt(black)?