Okay I've searched the boards, but can't make heads or tails out of what has happened here. It's not because I've got a Atmega 328 and need to select the right board, and the correct ports are selected (I only got the one on my laptop and nothings changed on my Mac), plus when I press upload it does start to blink, but just stops.
On my laptop running Windows XP and version Arduino 16, when trying to upload the Blink example, just to have something generic to test with, I recieve the following message:
UPDATED with verbose output:
Using Port : \\.\COM7 Using Programmer : stk500v1 Overriding Baud Rate : 57600 avrdude: ser_open(): setting dtr avrdude: Send: 0   avrdude: Send: 0   avrdude: Send: 0   avrdude: Recv: avrdude: stk500_getsync(): not in sync: resp=0x00 avrdude: Send: Q   avrdude: Recv: avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51 avrdude done. Thank you.
While on my Mac mini, also running version 16, I get this message:
avrdude: stk500_recv(): programmer is not responding avrdude: stk500_recv(): programmer is not responding
I've gone through the troubleshooter on the website and can't find any logical reason for this behaviour.
Could the atmega be having some issues?
Forgot to mention it's a Duemilanove, and as mentioned I'm on both Mac and PC, and I have been able to upload ever since I got it.
This might have been happening before, but I did not notice it. I just noticed that when connecting the Arduino to my computer I recieve a strange LED blinking sequence. I will write it down one line per blink, with the LED names on each line, so if RX & TX is on the same line, the blink at the same time. Empty line means slightly longer pause then just the blink of the eye.
RX TX L RX TX RX TX RX TX L L L L L L L L L L L L