I was recently asked to go to a clients house to find out why the internet was not working on one of his PC. The other PC was working fine. The first thing that I noticed was that the PC was not getting an IP address from the router. I tested the port on the router and found that one port had failed. Further testing showed that the network card in the back of the PC had also failed. Talking to the client it seems that there was a thunder storm in the area a few days before. It looks as if an electrical surge had travelled down the telephone line to the router, blown one port on the router and the network card on the PC attached to that port.
I replaced the network card in the PC and used one of the other empty ports on the router and all was back to normal. The client was happy to get his PC working again but upset that he had been sold a surge protector by the store he brought the pc from which had not protected his equipment.
I explained to him that the surge protector was only designed to protect equipment from small spikes in the normal domestic electricity supply and not from a massive spike from an electrical storm. If a storm is in the area it is still important to remove the power plug from sockets and also disconnect the telephone line.
The other thing to remember is that if a surge protector has seen a massive spike it is wise to get a new one so that yoru equipment is still protected.