Check to ensure you are plugging them into the correct audio port and that the speaker jack isn't digital.
Most computer speakers use an analog stereo 3.5mm jack. SOME have a mono jack that carries a digital audio signal. This type of audio port may be incompatible with the speakers OR the other way around. The speakers may have a digital mono plug and will not work in an analog stereo port.
Also, install the newest drivers for her laptops audio card/chip.
Ensure that the master volume and the other volumes are all turned up and not muted.
Test her audio port with headphones.
Try different ports even if you are fairly certain you have them plugged into the correct one.