Screen Only Brightens When Charger Is Plugged In

I am using a windows 7 Acer laptop, and the screen only brightens when I plug in the charger. Also, the battery gets used up too quickly, even though I have the computer on 'power saver.' Downloading Bios or a brightness control won't work. The lever goes up and down easily when I bring up the 'adjust screen brightness' screen in the utility folder, but the screen stays dark. On top of that, the lever refuses to budge when I bring it up from the taskbar. Does anyone else have this problem? Please help!

It's normal, Every laptop get brightness once they are charged...Se your Screen brightness..

And check your battery. They may wear out sooner than expected. Malfunction... whatever.

Check with Acer on how to fully discharge your battery. This will/should recovery your battery to normal operating range and extend the life of your battery.