I have a Toshiba L755D-S5109 Model # PSK32U-03P00X. I am having an issue with it staying powered up. I just purchased a new battery. The power light and battery light will start flashing and within 5 mins it will shut off without warning while plugged in. It did this with the old battery. I assumed with it being 4 -5 years old that maybe the battery was no longer good. Even with the new battery the laptop continues to shut down while plugged in. If i try to boot the laptop without it being plugged in it says the battery needs charging. Could I possibly need a new power supply?