Hello Roy,
I would start off by checking your wiring for all of those devices, you are having a power issue. It could be a bad power strip or a poor or loose connection on the back of her PC or even at the outlet.
You could try to move the printer to another outlet that is separate from her computer. Lastly, if you purchase a UPS (Uninterruptible power supply) and put her computer on that her computer should no longer shut off when you print.
Laser printers pull a lot of power to warm up the heat the fuser roller.