I saw this movie I think on h.b.o. When I was just a kid. It was about a nerdy boy who is befriended by a popular girl in the boys bathroom at school on his birthday in a nasty prank. He finds a way to kill them I don't really remember how I think it had something to do with the gas in the science lab. Anyway after the popular kids die their ghosts haunt the burnt down school and he goes back for some reason and ends up dying and then their ghosts torment him for eternity. I've been looking for this movie since I was very young and I've never been able to find it. I got up early one morning when I was like 10 or 11 and saw it on cable. It was like 4:30 am I was a kid I have wondered my whole life a about that movie. Please help, I'd love to see it again.

Not a complete fit, but maybe Slaughter High (http://www.hysteria-lives.co.uk/hysterialives/Hysteria/slaughter_high.htm)?