battery vs AC power

Do you have a question? Post it now! No Registration Necessary.  Now with pictures!

my laptop keeps "switching" to battery power even though the AC power
cord is securely attached to the computer.  I then just simply unattach
then reinsert the cord and it will work for hours (or sometimes switch
right back to battery).  Quite random.
I've heard everything from the DC jack, to the motherboard or the power
inverter board, or the AC adaptor (I don't think it is this since
reattaching it, can work).

I have a Compaq Presario R3360US.

Suggestions?  Thoughts?

Site Timeline