So i recently installed windows 7 on a laptop my brother gave me and it had windows 8 which i sort of disliked... And it installed nicely, It even got to the part where it made me choose my time zone and name the PC. Then it restarted, and now whenever it tries to boot up, it boots up, shuts down, boots up, shuts down endlessly. I'm really noobie when it comes to computers, my brother knows how to fix stuff like this but he's not available atm so i was wondering if someone could help me asap