AC adapter unknown, battery not charging

Hi,

When I start my computer an error message says

''The Ac power adapter wattage and type cannot be determined.
the battery may not charge.
the system will adjust the performance to match the power available
please connect a dell 150W AC adapter or greater for the best system performance.
Strike the F3 key (before F1 or F2 key) if you do not want to see power warning message 
strike the f1 key to continue, f2 to run the setup utility''

In the BIOS screen it says my AC adapter type is unknown and my battery is not from DELL. But I AM using the AC adapter and battery that came with my laptop. I tried to update my BIOS, but updating BIOS requires at least 10% battery and since my battery is not charging I cannot have it above 10%. I read this http://www.laptop-junction.com/toast/content/inside-dell-ac-power-adapter-mystery-revealed