Mouse / Battery Problems

I will try and be as concise and to the point with my problem.  Currently, I'm using my wife's laptop because my Dell Inspiron 9400 takes too long to type anything out.  Two days ago, my laptop was fine, but yesterday (7/19), I noticed my cursor not moving very well when using the touchpad.  I don't use a mouse as the touchpad works fine for me.  I'm not sure what the problem is, but my battery is also not working as well.  If it's not plugged in, then the laptop will not work.  When it's plugged in, and I click on the little plug icon in the system tray, it says "On AC Power".  When I right click that and select "Power Meter", it says "Total battery power remaining:  Unknown" and below that it says, in reference to the #1 battery, "Not Present".

My battery is intact on the laptop so of course it's 'Present'.  I'm not sure why this is happening all of a sudden.  My questions are simple:

1) Do I need a new battery?

2) Can my battery be causing my mouse/cursor to be going nuts like it is?

When I try to drag my finger on the TouchPad, it moves somewhat sporadically and requires me to push my left mouse button more than once to open a folder, etc. 

Please HELP!