She had been running it on battery a lot the fix for that one was a new battery.
There are now thousands of posts about this one. From my work I find that 98% of the time it's just a battery or charger issue. Replacing one or both has been clearing it up. In the outlying cases it's been the motherboard which means the end of the laptop as a portable battery powered unit.
My acer laptop constantly has to problem of 'Plugged in, not charging'. I frequently, almost every time I start it up, have to uninstall the Microsoft ACPI-Compliant Constrol Method Battery, and it takes usually two uninstall-reinstall attempts before it begins to charge again. It isn't the computer charger, since I've brought an entire new one to try to fix the problem, and there is no way I can remove the battery because I don't think my laptop has a removeable battery. What I need to know is where to go from here, because I'm sick of having to constantly uninstall the ACPI Battery.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic