Dell inspiron 3521 battery not recognised or gets recognised not charging

[dvtrv]

Hi,

I have a Dell inspiron 15r.

even with a new battery I have a flashing white and red light on batter indicator on front of laptop.

I’ve followed instructions to unplug, press power button for 15-20 seconds, cleaning battery and laptop points that connect battery.

nothing appears to work.

I'm running windows 8.1

thanks in advance for any assistance.