It does not have room for an internal drive, but you could attach an external drive to the eSata port or one of the usb ports.
Sometimes it's possible to remove the cd drive and replace it with another hard drive, but I'm not certain that's an option on this machine and you may not want to be without a cd drive even if it was possible
thanks I thought it only had space for one & I haven't looked yet but I saw a link to someone adding a 2nd drive to a DV7 but it may not have been an Entertainment PC. My model is DV7-3105ea
Do you mean just replacing the drive that is currently in the machine? You could certainly do that, but I read it as actually adding another drive so that you would have two.