How to test that a computer was even properly constructed.
Put it on a glass table (because many other materials are
actually electrical conductors and would subvert the test).
Now walk about with leather slippers to generate strong static
electricity. Then touch the running computer; each time
shocking a different corner of computer case, keyboard, or
monitor. This strong static electric discharge will only
upset improperly constructed computers - especially a problem
with homebuilt clones.
Many computer builders have never learned basic concepts.
One reason why a motherboard connects to chassis plate via
only one conductive standoff is this test and other equivalent
environmental events.
Earthing has no effect on static electricity - contrary to
popular myth. Static electricity is a current that leaves
your shoe, travels down your arm, uses table or whatever to
get into carpet where the electric circuit terminates on other
side of that shoe. Note a complete electric circuit where
earth ground is not part of that circuit. Simply put: somehow
a static electric discharge is forming a complete circuit that
apparently includes phone and computer. Circuit that may not
include critical internal computer parts if single point
grounding was used. You must find a complete circuit that
enters and leaves computer electronics.
As for that surge protector recommendation - anything
effective would already be on that modem. If that grossly
expensive surge protector did anything, then components that
cost less than $1 would do the job even better. Components
necessary because modem or whatever was missing essential
functions.
Where is protection effective? Start by first discovering
the circuit path for static electricity. That path must not
pass through computer. Example. Disconnect either phone or
modem from phone line - then reproduce the static electric
discharge. What happens? Did we just eliminate the incoming
path? That is how reasons for failure are first located; then
corrected.
BTW, I use static electricity as a tool to located
improperly constructed computers and even improperly safety
grounded electrical outlets. Static electricity can be a
powerful diagnostic tool.
