Just wondered - how long would you expect a laptop to run on battery power? I have just bought a new one, made sure it was 100% charged, and powered the laptop up whilst still on mains, then unplugged the charger. After less than 30 minutes I had screen messages saying 5% power left. Does this sound about right, that you would only expect something like 30 minutes from a battery before charging?
Depends what laptop you have. You say you have bought a new one...Is that reference to battery or laptop.? Does your operating manual say anything about operating on battery and an approximation of the time it will last before a re-charge could be necessary.? Some computers have batteries which can last up to 6 hrs. As an average I would have thought two to three hours.
Click on the power icon and choose economy, it may run a bit slower some of the time but your battery should last longer. Also turn down the screen brightness as much as is bearable.
Try charging it up to maximum and discharging by running a DVD. Then again. If after that you don't get more than at least 2 hours, it is probably a crook battery and should be taken back for a refund/replacement.