When you say that you bought it a few months ago, are you talking about the battery or the entire laptop? If the laptop is under warranty I would suggest calling Dell tech support as it may be a MB problem or a problem with the battery itself. You could try a reset by disconnecting the battery and adapter, pressing and holding the power button down for 30 seconds, then reconnecting everything and rebooting the system.
Hi. When i open my laptop, this message comes: I bought it a few months ago..... Any suggestions?  
inspiron 15 3511 does not recognize the battery - SOS