the popping sound your hearing is actually the sound of overheated circuits with miniature sparks. And seeings as its your screen thats affected (by screen i mean display image) it leands me to believe that the video card is overheating. This could be cause its eighter the card has run loose or has cold solder. Unfortunately your card is on the main board. Have you ever openened a laptop before ? I'm guessing not .. Ok here are your choices.
1.) leave it as is until it completely goes
2.) take it to a shop and have it sorted out (recommended if you dont have experience)
3.) try it your self,,
now the fix for this involves replacing the main board, however lets open it up first and see if we can fint anything that has gone loos (cables screws etc) in the even we dont well we have to get a new board.
these instructions take you from disassemble directly to main-board replacement.
http://www.irisvista.com/tech/laptops/toshiba-satellite-a205/laptop-disassembly-1.htm follow them to the detail for disassemble, remember loose components or mainboard replacement.