If you have your PC owners manual it will say. If you don't have it then you will have to open up your box and investigate. There is usually room to add one or more external drives. On some boxes/enclosures, you can install a disk drive on the top of the box and the enclosure covers it. Some boxes have extra disk drive bays. You might have to add a controller card. I can add four additional drives with my one controller card. If you don't care about how your box looks, you can do what I did. I have my box exposed, i.e., I did not put the enclosure back on so I could install another disk drive and it sort of just dangles there. Happy When there is a will there will be a way. Good luck. I have four internal drives in my desktop.