Can't load Minecraft

When I click to load Minecraft, it comes up with the new launcher. I then press play and the launcher disappears. Nothing happens after that! I tried relaunching it but it says 'Game already running'! This is very frustrating and I would like to know how I can fix this bug. Minecraft is the only way that I can play with my friends and now I can't! Please give a reply as quick as possible. Thx!