Yes, it will be video card device drivers.
Over the last few years browser developers have started to use video card hardware acceleration for rendering. You can find details here,http://msdn.microsoft.com/en-us/hh562071.aspx
Quoting from the Microsoft article,
"It's critical that you have appropriate device drivers installed to make the most of your configuration. Many manufacturers have recently updated theirs so that GPUs can work correctly with hardware-accelerated browsers."
You can also manually change the HW setting under the IE Advanced tab in Internet options.
"Use software rendering instead of CPU rendering"
Your family friend would probably also find that some 3D games don't work correct as well.