AC power adapter

I'm having a problem during the PC start up process.

PC- Dell Inspiron 6400
WinXP SP3

I get this message when the PC starts up.

The AC power adapter cannot be determined. This will prevent optimal system performance. To resolve this issue try to reseat the power adapter. F1 to continue, F2 setup etc.

I usually hit F1 and the PC continues on. Recently it takes awhile to start. My laptop battery is not even detected for awhile now and the usual "AC power" icon at the bottom of the screen is also absent.


Is the problem with the physical AC adapter? Should I change it?

or

Is it a windows glitch?

Thanks in advance

 

Thanks much