check your power supply output using a small volt meter (radio shack has them for less than ten bucks) after that you need to check the output from your main board. this requires you to put meter on leads of power connector first without power, then with battery power, and lastly the power adapter. Go to manufacturers site to get specifications for your exact model. What this will do is eliminate the components you are testing based on their output. Whichever is below specified output are to be replaced