Ok, first try this: connect your device to a Wi-Fi network and enter the settings - about the device and look for manual download, with this option look for any updates, if there is any, let it download and update the device, it is not 100 % sure it is restored but you can try to avoid the long procedure.
If it could not, you should do the following on a pc:
1. Search the firmware on the page sammobile.com/firmwares, look for your model and the list that appears you look for your country and the latest version.
2. Unzip the firm and download the latest version of ODIN and open it
3. Reboot the phone in download mode, for this, turn it off and on again by pressing the home and volume buttons - if it went well you get a warning that you can damage, press volume + and continue, you will see a screen that says downloading
4. Connect the cell phone to the PC.
5. In Odin look for the AP button and press it to look for the signature that you downloaded at the beginning, in the options that it gives you to the left preferably do not move it, just make sure that Re-Partition is enabled and enabled Auto Reboot and F. Reset Time.
6. You give Start and you wait a good while in which it ends, it gives you time to prepare a coffee or to do something more hehe, it takes like 15 mins, in the part above there is a green progress bar, when it finishes it is going to restart the phone and yaa.
* Another option to install the firm is looking directly from the samsung page in the support section and in some models and countries it throws everything you need to do it, I do not know why in my country it does not come out anymore :(
Note: The phone worked correctly before the hard reset, if it was not hit or something strange should work after the installation of the firm, if it still does not work then the problem is physical, and in that issue I have no experience = (