Problem with iPod dont know what is the problem

ok so my sis has an iPod and she went to update and it got stuck on recovery mode. after awhile i fixed the recovery mode problem but the new issue is that once she turns it on give it a minute or two and it freezes and the screen goes white and it stays like that till the battery dies out. any idea on the problem i was going to change the screen thinking it could be that but im not sure as of now. thank you for ur time.