Can't upload anymore, is my Arduino dead?

Development Tools IDE 1.x
1

Yesterday I was tinkering with some code, when suddenly I couldn't upload anymore. I got the following message:

stk500_recv() programmer is not responding

I have a duemilanova, and my pc is running Ubuntu 14.04.

What I have tried so far:

  • selecting another port in the IDE
  • unplugging, resetting
  • disconnecting all shields and external components
  • using another USB cable, connecting to another port

Nothing works so far. When I connect the board, the power led lights up. When I try to upload something, the RX led flashes three times, but nothing after that. So I figure the board is communicating with the pc, right?
I'm afraid I might have destroyed the processor, because when I connect it, it immediately becomes warm, even without anything else connected. My circuit also had a 12 volt part, so I suspect I might have accidentially sent 12 volts to one of the inputs. Is there any way to check if the chip is still working? And if it's ruined, can I just replace the chip (an ATMega 328)?

2

If the 328P chip is hot, it's a goner. Replace it. 12V on an IO pin will do that.
Get yourself another chip or two,
http://www.dipmicro.com/store/index.php?act=viewCat&catId=595
or some blank ones that you can boot a loader on using a bootloaded chip as the programmer:

Altho for the slight difference in price, getting prebootloaded parts seems like a deal.