17 R1, swapping between AC and battery every 20 seconds

Hi all,

I'm Having an issue with my Alienware 17 R1 (warranty ended on 5/24/16) with charging the battery.

if I Plug the laptop in it keeps swapping from "AC powered - Charging" to "Battery Power" about every 20 Seconds, swapping back and forth (the battery is charging when it says AC powered).

If I unplug the battery (take back of and disconnect) it runs on AC fine and if I just run on battery power it works fine again.

The Battery doesn't charge if the laptop is off at all.

I've tried Unplugging everything and holding power button down (Battery disconnected) and I've tried Device manager and uninstalling driver (both with the battery connected and disconnected), Bios is up to date to.

I've bought a new Battery and Power lead just in case but still same issue.

I've also run the Diagnostics at boot (F12) and the only thing wrong (Battery etc is fine) is it keeps swapping the status of the AC Adaptor from "180W AC adaptor" to "Not installed" again every 20 seconds which is obviously the issue but unsure how to fix??

Anyone had this issue or know how to fix it because every forum I look on says try the above options??