yes, you can
BUT you have a 500watt PSU for a R9 280X big no-no, you'll defiantly get a blue screen as that PSU is not enough to power that card and your other components well. Since this PSU is already in the case, it is a cheap one, not good and it is from the company thermaltake, who make terrible PSU's anyways, please avoid this and get a separate case a 600W Corsair/Antec/Seasonic PSU.