PROBLEM WITH ERROR: verification error, first mismatch at byte...

Hello,

I have just bought an arduino uno.

when I try to run the (first) sketch "blink", on the screen appears the error:

"verification error, first mismatch at byte 0x0298 0x82 != 0x80"

How can I solve it?

Is it a problem of the device? Do I have to chenge it?

Just to let you know I have already tried to change usb cable and re install arduino.

Any help will be appreciate.

Cheers