I took apart my nerf n-strike rampage to get out a jammed dart. How do I put the nerf gun back together?

Sometimes for old systems like the game boy advance it will freeze up with age. Try blowing any dust out of the spot where you enter the cartridge. If that does not work, through clean the inside of the cartridge entrance with a clean cloth. If it is just not working for a specific game, do that process for the inside of the game cartridge, too. However, being old technology, eventually gameboy advances will just stop working.