my laptop is dell inspirion 1564 . if im on working suddenly screen going white but system is working . i don't no what is the reason for it. i was checked my ram also but i didn't find any fault in ram.pls help me to sold this problem

Your LCD screen could have problems, maybe crack. The video cable connecting to the screen is loose.If you have an external monitor, you can connect to your dell laptop and see whether you are able to view the screen as per normal. Try doing this

1) Take our battery and power
2) Hold power button for 30 seconds
3) Boot your laptop with everything connected back