one volt should not matter as the input voltage on the original sould have a tolerence of about 5%. wattage does not matter, as that just means that the adaptor can handle more current than the other one. wattage is voltage times amps. your computer will only draw the number of amps it needs, current is not supplied like voltage, but is taken in the amount the device needs at that moment. voltage is supplied and should be close to a constant value. make sure to check the polarity of the plug and match it to your laptop.