I am using an Uno with atmega328P-PU on windows 7. Every time I try to upload I always get exactly the same error message (even on 2 different computers I've tried, both windows 7). This is the error message:
avrdude: verification error, first mismatch at byte 0x0000
0x0c != 0x00
avrdude: verification error; content mismatch
I have seen similar messages but none exactly the same, any help would be most welcome. Also I am fairly certain the bootloader is functional, as pressing the reset button causes the pin13 LED to blink. Power is fine (pwr LED on, using USB), and I am running it off the board so hopefully there aren't any circuitry problems. Strangely the board worked fine before, although in between working and breaking I put it on breadboard and tried to use Serial.read(). This shouldn't have effected it power was regulated 5V and also there is no serial traffic before uploading. The chip can't be burnt out as the reset LED blink still works, it seems to be a problem with uploading only. There doesn't seem to be a program running on the board either.
additional info:
board: Uno
chip: 328P-PU
OS: windows 7
IDE: 0022
Code: "blink" example for testing
COM port: 5
Drivers installed: yes (0022)
Thank you to anyone who can help.