Most laptops have a one year warranty. Use it. The expense of a new motherboard will just upset you.
My note book battery recently has taken a turn for the worse. It fully charges in about 15 minutes and discharges in 5 minutes. The battery has been handled properly and charged/fully discharged a few times a week (the battery is only 6 months old). I think the problem may be w/ the power management portion of the software. Any ideas I can try besides buying an expensive new battery?