you sound like you have a discharged battery. if your power unit is indicating it is lugged in when you insert the plug into the outlet then your battery is most likely discharged. A commonly reccommended suggestion is to let your computer adjust your power settings for you and to keep it on a balanced power setting. When using your laptop, if possible, keep it plugged in. They are made to be portable but justr like any other rechargeable battery, when you alllow them to fall below a certain threshold, they lose thier ability to hold a charge and eventually die. I suggest you replace your battery and follow the suggestions and recommendations previously mentioned.