Download issues

As my friend tried to download leauge he hit an issue. During the part where you select your username. After the download finishes he simply cannot click yes after he enters the name he wishes to have. Spamming it doesn't work, clicking and waiting doesn't work, the screen just sits there. Not changing. I would love to play with my friend and would like to hear if anyone had this problem and knows how to fix it, or if it is needed to be fixed on developer level.