I just got a steal on a laptop at a local close out electronic auction. It doesnt have the hard driver. Im not to tech savy. I know how to use computers pretty good i dont know much when it comes to the brains on the computer. I heard you can run a computer without a harddrive is that true? How would i know what hard drive i need to get the model is as follows ASUS ROG GL502VS-DB71 i know its a 1tb 7200 rpm hard drive. I dont know how many inches it is or the size i would need for the replacement, how would i find out? Will it be operational when the new hard drive is put in? Or will it need to have something downloaded like the OS?