Laptop turning on problem

Hello,

i have a dell latitude d630 it works fine i didn,t use it for a month and now i am trying to turn it on but it isn,t turning on. the battey was on 36 percent when i turn it off and didn,t use it for a month... if i plugged in the charger also it works fine if i remove the charger it will works fine on battery too.....but when i shut down it then again it need charger to be plugged in to turn on... is there any one to help me to solve this problem plz