Remove the battery and unplug it, then press the power button for five seconds. Are both Macs the same model? If so you can test her keyboard on your machine.
Try your MagSafe on her machine and hers on yours. This really sounds like a liquid spill case. Look at her magsafe port and inspect for corrosion. Check her battery for swelling. If the external keyboard is working, reseat the keyboard to logic board connector. Of course you can try repairing her hard drive with Disk Utilities while in Target mode if you can get hers up. Has her hard drive died now? Do you have access to an external enclosure to test her drive in?