aptop screen fluctuates

hi everyone.i bought a compaq presario v6425tu notebook model 2 years ago.it doesn't give enough backup(10min) so i work on ac power all the time.but now my laptop screen gradually fluctuates while working(brightness increased and decreased also).should this is bcoz of my battery problem or there is something wrong with my screen?

 

Take out the battery from your laptop, since you use ac mainly. Maybe that'll help.

 

This may be due to two reason. To solve this check your Brightness setting in Control Panel->Hardware and Sound->Power Options, If problem persist again then it may be due to VGA cable of your laptop.