[samy_1985]

I understand you don't have a cristallball, I thought you will have a solution for the sudden license issue and a 'next/finish' button unavailable, I've already done everything as in your 1st post instructions, I wouldn't disturb you for this, as a final option I  directly ask you. 
Please I've done the following, uninstall ISTA, delete all registry linked to ISTA, delete folder in C, run cleaner, installed the new version, again same issue when I try to copy paste license NEXT button is grey not available to click on it.
system requirements scan results photos attached with installed and not installed ista.
cheers