Compaq Presario 725US Battery issues

MY friends computer keeps turinging itself off, even when it is plugged in. It thinks the battery is dead even though its charged. And the icon in the bottem left corner wont appear telling how much battery is left or that it even detects a power source. All efforts of going through the control panel and changing settings havent made a difference. So I was thinking my friend might need to download a driver or something. Or it might just come down to reformatting. My friend had to send it to the manufacturers recently to get the screen fixed and since then the computer has had this problem. So if anybody has any suggestions please drop me a line.

Apernicus