Not sure if you understood it... You can reset the trial, but the trial itself will be canceled the following day.... So it's kind of 1 day thing.
If this doesn't work for you, it's due to a problem specific to your system. An alternative solution has been suggested here.
After registering on the current ESET HOME website, you can obtain a trial version directly. After creating an account with a temporary email address, enter the activation code into your computer's expired ESET product. You do not need to use this script to reset the trial period if your country allows the legal use of temporary email addresses.
this method is for Windows only... I would look into finding what the program writes to save it's installation properties.
You can actually skip the .reg files and the manual entry deletion, I assume you guys are unexperienced with command prompt. You can delete the entire key and its contents in one go using this CMD command (don't forget other entries): reg delete "HKEY_LOCAL_MACHINE\SOFTWARE\ESET\ESET Security\CurrentVersion\Info" /f Instead of trying to delete one by one, you only need to disable Self-Defense and close ESET, there is no need to run this commands in safe mode.