problem from starting

Hi,
i have just installed my arduino and all seems go well.

I have tried to start first sketch: File-Exemple-basics-blink, but led didnt blink and the interface shows this error:

avrdude: verification error, first mismatch at byte 0x0002
0x64 != 0x5c
avrdude: verification error; content mismatch

So i tried to install it in other PC, and nothing changes.

What gone wrong?

Thanks so much

Which Arduino board? Original or clone? Which IDE version? Which operating system?

I will not be able to help you, but I'm sure that that information will help others to help you.

Original Arduino One, IDE 1.6.7 and windows 7.