Computer breaking down ! HELP?

Hello. my sons ADVENT laptop is making this crackley pop noise. I've restarted it and it was just so slow it took like 10 minutes just for one of the icons to appear on screen. Hes had it for 5 months and it was working wonderfully. Ive tryed again to restart it and it stays normal for like 2 minutes then crashes and starts making the strange noise. Is his computer broke ? Please help , he loves his computer and needs it for his GCSE's. Help pleasee