an unhandled exception occured in firefox.exe[1234]

hai all whenever i try to open firefox or gomplayer or any songs or video..i get a pop window called an unhandled exception occured in firefox.exe and all of a sudden everything gets closed.... i googled this info..and got a solution has turn .. because it changed your windows DEP settings from "Turn on DEP for essential Windows programs and services only" TO "Turn on DEP for all programs and services except those i selected:......" i even tried to change the DEP settings still the problem persists... how am i solve this..this is actually killin me...couldn do anythin for the past two days... i badly need a help......... Thank you in advance....