Destructive surges typically don't cause visual damage. Such
transients have too little energy. However if surge damage causes the
power source to output excessive current, then the damage is made
visual by that 'follow on' current.
To start on a "Time Computer to look at which has had a power surge",
first ask what could have been the incoming and outgoing paths
(assuming it was surge damage). For example, to damage a power supply,
incoming would be AC mains and outgoing would be what?
More often, damage to a computer enters via safety ground wire -
bypassing a power supply that has so many layers of protection. (Power
supply specs - if it is a minimally sufficient supply - will even state
how many thousands of voltage that supply can withstand).
A most often path for damage is incoming on AC mains and outgoing via
telephone line. Other possible outgoing paths could be USB port,
printer parallel port, network cable, or even mouse cable. In each
case, a transient first flows through everything in that path - and
only then does one (or a few) item in that path fail. To have surge
damage, first there must be an incoming and outgoing electrical path.
This assumes it is really surge damage. Too many who have not a clue
then assume surge damage - even when damage occurs during a power loss.
For example, the power supply system is not just a power supply.
Others 'sub-system' components could be damaged. A meter would have
confirmed or identified a defective power supply 'system' failure in
less time than it took to remove that supply. In your case, first
voltage measurements start with the green, gray, and purple wires from
power supply to motherboard. If voltages on orange, yellow, and red
wires exist AND are above minimum values, then computer could be
working, but visually appear dead. Just another reason why your first
test should begin using a 3.5 digit multimeter - and not remove
anything until important information is first collected.
