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So I've got my computer in my bedroom, connected to the router downstairs via a switch, homeplug and another switch. I have Ubuntu and Win7 installed.

So I'm doing some Lua scripting in Ubuntu and suddenly the computer powers off instantly. No warning at all, other devices are unaffected, so not a powercut. I power it back on, boot into linux and there is no internet. Ping reports 'network unreachable'. I can find no working solutions online, so I boot into Windows. No internet either, no IP assigned, no DNS, 'general failure' for ping. Probably not an OS problem, since I hadn't used Windows for hours.

I assume that the router or network infrastructure must be the case. I reboot the router, get as direct a connection as I can, but with no luck. I put everything back, and just to be sure, I check a device branching off at the same point that my PC does: It can access the network and internet just fine. Not a network infrastructure problem.

I have no idea what's going on, and I consider myself to be an experienced computer techie. My motherboard is an ASUS P5N-D, latest bios, if that helps.

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up vote 1 down vote accepted

sounds like your NIC just died. What is the condition of the cables that connect to that NIC? Could there have been a short that sent some juice into the NIC? I've had a PC shutdown due to bx and network cable rubbing and fraying in the wall and shorting, frying the NIC. The switch port was unaffected because the switch can usually handle a good amount of juice. Look for blown or burnt components on the NIC (if its a Nic on your Motherboard, then try a NIC card.)

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Thanks. It seems my onboard NIC died. I added an external card and all is good. I know it's obvious, I suppose I just didn't want to accept that a part of my reasonably expensive motherboard is now permanently dead :) – Hamish Milne Jun 9 '11 at 16:37

I think the only thing left to check is the network card itself are the lights blinking when you are connecting the cable? If not, and you didn't disable the card in bios (check?) or OS (check?) you might have fried your card for some reason.

Check dmesg (like: dmesg | grep your_network_card_module ) in ubuntu and/or event viewer and device manager (especially hardware state) in Windows. You can also try troubleshooting assistant in Win7 - they are pretty good :) Good luck!

share|improve this answer seems only the orange light is flashing. Damn. – Hamish Milne Jun 9 '11 at 16:37

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