Laptop is 4 months old. I usually use it plugged in..but when I use it on Battery power the screen is very dull...Is this normal? It will last approx 2 hours on Battery but because of this I usually plug it in.
Yes it is normal. The screen uses a light, which uses up battery. Therefore to lengthen the battery life the light is dulled when using the laptop with just its battery, so it uses up less power. There is mostly likely a setting to change it if you look in your manual. I cannot advise on your particular laptop as they are all so different!
Doesn't your manual help? My Medion manual has explicit instructions for all sorts of adjustments using various function keys. Fn + F7 brightens the screen on battery but of course battery life is shortened.
It's actually a Windows function accessed through Control Panel > Power Settings. You can chose how you want your computer to behave when operating on mains and battery. You can set it up to be a laptop or desktop and so on. Each gives the opportunity to change things like screen brightness. It's just possible that when you chose the Power Settings option it may direct you to a specific version supplied by the laptop manufacturer. But it's easy to change many different parameters like how soon before the HDD turns off or the screen turns off.