The first thing I would do is be sure if there is a ground present in the box.
A lot of older houses used a grounded system but installed 2 prong outlets. If
so the adapter works as long as you connect the ground tab to the center screw.
With that connected try a 3 light tester.
Better is to use a self grounding recptacle ... all assuming a ground is
actually present in the box.
If there is no ground present she really should try to get a circuit pulled in
for the PC. Surge protectors are not very good without a ground.