Even rechargeable batteries don't last forever, but if you can't power your laptop on even when it's plugged into an alternating current outlet, the problem is probably not your notebook battery. A standard notebook computer should run on alternating current even if the battery is removed entirely. Unfortunately, the resolution may be a bit more complex than simply buying a new notebook battery.

Damaged or Incorrect Charger

Your lack of notebook power may stem from a charger that isn't working. If the AC charger cord is damaged or the voltage converter -- generally a large block in the middle of the cord -- isn't working, your laptop will not receive adequate power. An incorrect power supply can also cause this problem. Not all laptops use the same amount of power, so substituting a friend's cord for your own can damage your computer and lead to a lack of power. Solutions for this problem include purchasing a new power adapter directly from the laptop manufacturer to ensure the proper power source or buying a universal adapter. If you opt for the universal adapter, they aren't totally universal. Check the bottom of your computer for the voltage and amperage rating, generally in a format similar to "19V DC --- 3.65A," which means 19 volts of direct current at 3.65 amps. Purchase only an adapter that matches or is slightly under this power requirement, never over.

Dead CMOS Battery

The CMOS battery, also called a motherboard battery, supplies a small amount of power to the chip that runs your computer's basic input/output system, which tells your computer where to look for information each time it boots. Without power to this system, your computer will not power up at all. The CMOS also stores your date and time information. Generally, the CMOS battery recharges each time your computer is plugged in, just like the standard notebook battery. However, this battery stays on to retain memory even while your computer is off. If your computer was off and unplugged for an extended period, or if you noticed fluctuation in your date and time settings before you became unable to power up, chances are your CMOS battery is to blame. Replacing this battery requires expert-level technical skill to avoid damaging the surrounding chips, and attempting to replace it yourself may also void any warranty on your computer. The best bet to fix this issue is to take your notebook to a certified repair technician.

Faulty Jack

Another possible cause for lack of power is a faulty power adapter jack. In this case, your batteries, both CMOS and standard, are healthy and your charger works, but damage to the jack or its surrounding wires prevents the electricity from going from the adapter to the battery. This problem is difficult to diagnose without consulting a repair technician, but if you have used the wrong adapter for your notebook in the past or if you spilled liquid into the jack or elsewhere on your computer, this is a likely culprit. Blow out the jack with a few slight bursts of compressed air in case it's a simple case of debris blocking the contacts. If this doesn't restore your charging capabilities, you may need to bring your computer in for service.

Other Possibilities

Your computer system failure may not have anything to do with the battery at all if you're experiencing a complete lack of power. If the AC indicator light doesn't light up with the adapter plugged in and you're certain that both the adapter and the jack work, your entire system may be damaged. A power surge or major exposure to liquids can cause complete electrical failure or damage to the motherboard and system chips. In this case, replacing the computer or its components may be the only solution. Before you go that far, however, remove the battery entirely with the laptop unplugged. Hold down the power button for at least 30 seconds to discharge any remaining power, and then put the battery back in. Plug in the laptop and see if it works. If the problem is caused by a software glitch rather than a hardware problem, this could fix it.