Computer wont turn on

This computer isnt that old, it did have problems before thoughh. It had been reset multiple times and the cdrive doesnt work properly. it also runs on windows xp.

so I was playing RS and then there was a pop. i didnt know where it came from and the computer was fine. then a while later the computer was going extremely slow on RS and then the mouse turned black and everything kept freezing up.

i let it be and it crashed so i started it up again, sent an error report while loading rs again and everything was all black squares instead of lettering. then microsoft error report said that there was a problem with the graphics.later after that it crashed again and each time i pressed the startup button it would light up then immediately shut down.

what do I do to fix this?

 

Something probably burnt. Open it and check that every hardware piece is fine, remove and reconnect to make sure.