I have a Dell Studio 1558 laptop that won't turn on unless I plug in my charger. Right now I'm using a 65W Dell AC Adapter. My laptop will turn on, but give me a message saying that it is the wrong charger and it won't charge the battery. I can still use the computer, but the battery won't charge. I have a hunch that this might be because the laptop requires a 90W charger. Is there any way for me to make the charger I currently have charge the battery?
Yes it sounds like your laptop requires greater than 65W to both be "on" and "charging."
In answer to your question, most laptops will charge on lower wattage adapters, ONLY if the computer is off.