Not surprisingly, that unit doesn't appear to be available here. And that one can only be shipped in the US (and may not work the electrics here anyhow).
Still, I checked the ethernet cable and noticed that it is actually plugged in through a surge protector that is supposed to protect from lightening (it specifically mentions lightening). That unit still operates perfectly so fat lot of use that was.
As for the no longer needed modem, I guess I'll just return to Amazon. They seem fairly good at giving refunds going of past experience with them. It's just a shame that we can't just tell the delivery guy to take it back. They don't offer that sort of return service here.
Although I seem to remember reading that the US store does =S

I mostly post links for anything I mention just for reference. I would think there would be similar units world wide. Sorry, didn't mean to imply that particular unit was available in Japan.
Anyway, hope you find something that works. . . =)

It did go through the phone line, or if it's a cable modem, through the cable line.
Those lines do hold electricity and can short out your devices. Unfortunately I believe most surge protectors for phone or cable lines prohibit the use of internet through them.

So the morale is don't give into your kid's whining. Does she have a DS or any other portable system? If so, You could have just let her play that instead of the Wii.

I was reading this post very interestedly as this is something that happens at my house a lot.
The thunderstorm doesn't even have to be that close. But if there's a lot of lightning, it will happen about every 5 minutes or so. There's two telephone connections in this room, and the socket will just give off a loud sparking noise. You can clearly see the spark, and if it happens at night the whole room is illuminated by it, it's pretty spooky. I was completely scared the first couple of times, afraid that it might damage something or even cause a fire, but I somehow got used to it.
One of the lines is connected to my modem/router, and it has happened that I even saw little sparks inside the modem. I never would have imagined it to work anymore, but it still does. I have seen sparks inside the device itself a couple of times now. Sometimes the router rebooted after it, but most of the time I don't even lose my DSL connection!
I'm really surprised that this can happen, especially since I live in an urban area with a well-developed infrastructure, and we simply do not have overland telephone lines here.

What you are saying seems to be very unusual. This should be a very rare singular event. It looks like an extreme case of over voltage on telephone lines. Are you sure it is related to thunderstorms?

Well it's definitely possible because it happened to me with my fiberglass cable used to receive broadband and digital TV. Everything connected to my network got fried except the TV because my Digital Receiver was between it and the cable. Modem, hub, router, laptop = all fried. And this with everything unplugged.

Oh. So, that's why they call it "ethernet" and the like.

Bonus. You have a spare modem. If another thunderstorm is likely to occur soon, protect the now spare modem and have it ready for if this new one decides to die, too.

Sadly not a bonus. Within the next 2 to 3 weeks or so our provider is switching to digital which means the current modem will no longer be compatible. Besides that, I can't really afford it. Shortly after buying Windows 7 a close relative of one of my coworkers died and a couple of days ago one of my wife's relatives died. This being Japan, like most other customs, a death basically means associates, friends, family, etc., having to give gifts of money (typically 100 to 200 dollars or more depending on circumstances).

It has happened about 20 times already, and I never noticed it happening without a thunderstorm outside, so I definitely think it's related. If it does happen, I will usually hear sparks about 2-5 times per half hour. But, to my own surprise, it has never damaged any devices so far. It doesn't happen during every thunderstorm though, I would estimate about every fourth one, when the centre seems to be rather close. And it always coincides with a strike of lightning outside.