1 Nickel

RE: Please confirm Inspiron Integrated Network interface dead

You had protector adjacent to appliances and so far from earth ground as to be all but completely disconnected.  So protection inside electronics may have been compromised.  You made damage easier.

But first, remember how electricity works.  If a surge entered on any one port, that same current had to be outgoing - at the same time - via some other port.  If that current was incoming on any one utility wire, then at the same time, that current was flowing into earth via some other path.  What was that incoming and outgoing path?  If one does not exist, then no surge existed.

Most common path is incoming on AC main.  A common outgoing path is outgoing via DSL (since all DSL must already have effective protection installed for free).  Damage is often on an outgoing path (to DSL); not on the incoming path.

View some numbers.  How does a 2 cm part inside that protector 'block' a surge that three miles of sky could not?  It doesn't.  How does its hundreds of joules absorb a surge that can be hundreds of thousands of joules?  It doesn't.  But an adjacent protector can only 'block' or 'absorb' a surge.  Suspect a sham yet?

Same applies to hardware protection provided by a UPS.  It does not exist once we include spec numbers.

Protection means a surge current does not enter a building.  Then that current need not hunt for earth ground destructively via appliances.  How were direct lightning strikes made irrelevant over 100 years ago?  'Whole house' protection.  That costs maybe $1 per protected appliance.  And is virtually unknown to a majority only educated by advertising.  And who forget that a surge needs both an incoming and outgoing path.  Those memory lapses are how $3 power strips with ten cent protector parts sell at obscene $25 and $90 prices to naive customers.  To customers who even forgot what was taught in elementary school science (ie Ben Franklin's lightning rod).

A protector is only as effective as its earth ground.   DSL is already required to have that effective protection.  Did hearsay, wild speculation, and advertising also forget to mention that?  I believe you have some installations and wiring corrections to perform.