No, you can use it, just can't overclock it, so the price you paid to get an unlocked CPU goes to waste because your board (an H77 board) is unable to overclock it, just able to run it at stock settings. If you haven't bought the board yet, look at the MSI Z77A-G43 - basically the same board, except with the Z77 chipset so you can overclock a K series processor, and it's only about 10-20$ more than the ZH77A-G43.