My minecraft FPS is low! (15fps)?

Hi, i have a toshiba satellite c660-2el laptop and it is over 5 years old. I play minecraft on xbox and decided to play on pc. (well, laptop) I realised my fps was low so i googled the best settings for fps and changed them and hardly anything changed. I then downloaded optifine and used it and again, hardly anything changed. I'm getting fed up of the extreme lag and getting killed at the cornocopia of minecraft hunger games. Could someone please tell me the best thing to so? Restore my laptop to get rid of viruses or whatever, Download another mod? Or buy a gaming PC or another pc. What is it on my laptop that slows down my FPS? I've heard something about the CPU and GPU and GB or ram or something like that, so any help will be appreciated!