Screen flashes frequently after some time
I have one Dell Inspiron 15 5458 series laptop. Its screen flashes many times automatically. By flashing I mean that its brightness increases immediately or decreases to zero suddenly only for a moment. I have googled for it and disabled 2 services from msconfig. But still, that problem continues. Also, sometimes when I try to decrease the brightness of the screen using the function key provided, laptop suddenly goes in sleep mode.
Please Help me with this.