Arduino not working

I have been encountering an error whenever trying to upload any sketch.
This problem is also encountered for all the sketches (including the basic blink program)
The error is :

avrdude: verification error, first mismatch at byte 0x0000
0x0c != 0x62
avrdude: verification error; content mismatch

I've checked the board and com port settings and they are both correct

thanks

Which board do you have?
Maybe bootloader is corrupt. Reburn it.

It's arduino uno