My board arrived today(uno rev'3) blink sketch ran at startup. Com3 is selected (windows 7 64 bit) and the correct board is selected. I changed the timings only to dip my feet in the water of programming and an error was generated. The error is "avrdude: verification error, first mismatch at byte 0x0002
0x61 != 0x60
avrdude: verification error; content mismatch.
I have read through several (lots of forums) and whilst I see people with similar errors the topic dries up before a conclusion is reached. The code compiles correctly and the board receives the program as indicated by the leds. The program does not run and the above error code is displayed, driver update has been checked and is up to date. I have downloaded several blink sketches from different sources and still get the same error. If I load different sketches I still get the same error. I am totally lost. My conclusion for what its worth is that maybe the bootloader program is not working correctly, but I am reluctant to make any changes at this stage because the board is brand new today. Any help would be appreciated
aheighway:
My board arrived today(uno rev'3) blink sketch ran at startup.
Where did you buy it from?
aheighway:
I changed the timings only to dip my feet in the water of programming and an error was generated.
Changed the timings of what?
aheighway:
The error is "avrdude: verification error, first mismatch at byte 0x0002
0x61 != 0x60
avrdude: verification error; content mismatch.
It might be helpful if you turn on Verbose output (in preferences) and post the full error/log.
Hello James thanks for the reply, it was purchased from Phenoptix via Amazon. I changed the blink rate from 1000ms to 500ms and tried to upload without success. I will do as you suggest and post this info here today. Thanks again.
Hello James, should I enable verbose output on both Compilation and upload or just upload, the compiler seems happy with the code and the error is only generated at upload.
Hello James, the verbose listing is over 9500 characters long and cannot be posted. This is with upload verbose only ticked.
Try pasting the log into a text file. Then attach the file to a post (available under "Additional Options...") when creating / editing a post.
Thanks James, 
I've been in touch with the supplier and they are replacing it. I have posted it back today so cannot do any more here. I do appreciate your time, and when I look at the information flow onto the board I'm convinced the bootloader is at fault but unfortunately I can do no more testing , Thanks again.