On Wednesday, February 10, 2021 at 1:58:09 AM UTC-5, Jim Joyce wrote:

Since someone started this thread up again, might as well point out
that if you were to plug a 3 prong surge protector into a two prong ungrounded
receptacle using an adapter, there are a few issues.

First, it's an old system and it's unlikely that a ground is present at the
receptacle box. An adapter is really supposed to be used by using the
wire to ground to the box via the cover screw. But very few are used
that way and even then unless the box is grounded, which is unlikely,
it's useless. So if you did that, the computer and anything else plugged
into the strip would not be grounded.

Next is the issue of what happens to the surge protection. Without
a ground, that path for the surge to dissipate is gone. You would
still have clamping though that would limit the voltages between
the conductors and between the conductors and the strip and
PC ground. So you'd have some protection, but not the best.
A GFCI would provide safety protection from faults that could
be dangerous without a ground, but it won't change the surge protection
issue as there still is no ground.