If you replaced your dead laptop battery and it still won't power up- perhaps your transformer (AC adapter went bad). I found this little article on the net. * Adapted From: Upgrading & Fixing Laptops for Dummies This article was excerpted from: Upgrading & Fixing Laptops for Dummies Say that you plug your laptop into a wall socket - you press the On button, but the lights don't flash, the screen doesn't change colors, and the earth doesn't move. The power doesn't be. To identify the problem, you need to understand the nitty-gritty of the electrical system. Nearly every laptop uses DC (direct current) voltage, usually in the range of 5 to 20 volts; almost nowhere in the world, outside of a laboratory, does that type and level of power come out of a wall outlet. Instead, when you connect a laptop to wall current, you use a power cord that includes a small box that converts AC (alternating current) of 110 volts (in the United States, Canada, and a few other places around the world) or 220 volts (the standard AC voltage in most of the rest of the world). The electrical connector rectifies or converts alternating current to direct current (removing one of the cha-chas from the back-and-forth movement of AC to yield a steady cha) and also transforms the voltage from 110 or 220 down to the needs of your machine. The adapter output can go straight to the motherboard, or the computer can divert that output to pass through the laptop's battery, recharging it. (Actually, most laptops include a bit of electrical circuitry that lets you use the machine at the same time as the battery recharges.) The adapter may not be getting the AC juice that it needs Is the power outlet live? Check it by plugging in a lamp or a radio to the same outlet - not the one above or below it - to see if you get any power. (Remember that you control some outlets with switches on the wall; Europe and Asia commonly have switches alongside most outlets.) Do you have the charger properly connected? Some chargers use interchangeable power leads at the end that goes to the wall outlet; this design lets you use the different-style plugs that you may encounter around the world. Make sure that you have the lead properly attached to the charger and the charger plugged into the laptop. The adapter may have failed Although many people call it a battery charger, you actually should call the equipment on most laptops a voltage converter that works with circuitry within the laptop to do two things: charge the battery and run the computer from wall current. The charger converts 110 or 220 volts of AC to DC voltage generally in the range of 5 to 20 volts; the conversion usually creates a bit of heat. The converter shouldn't get hot enough to boil your morning coffee, though. If you see smoke or smell the distinctive acrid odor of burning electrical components, carefully unplug the converter and look for a replacement. Adapter failure doesn't happen all that often. But a power surge; a poorly regulated current; or cut, crimped, or ripped plugs or wires may damage your adapter. Look for these clues if you need to figure out if the AC adapter is getting power from the wall and if the laptop is getting voltage from the adapter: * A small pilot light on the AC adapter: This light indicates the presence of power; if the lamp isn't lit, you may have a dead charger on your hands. * A little symbol or light to indicate the presence of an outside power source: Many (but not all) laptops have this indicator. If you don't see it, your laptop's adapter needs some help.