laptop cannot detect battery, help!

for some reason, last night my laptop came up with the little symbol in the bottom right of the screen, saying that it is plugged in, then i noticed that the battery symbol (which is normallly full because it is plugged in most of the time) has a big red cross through it. Upon hovering over it, it says no battery is detected, help please!

Hello,

Remove the battery and try cleaning the contacts, see if it works.

how to remove a battery from a laptop?

There's usually a slider somewhere around the battery underneath the laptop for you to remove it.

still nothing, if my laptop is not plugged in, its off....