I suggest you find a manual on Dell's website and see what you need. Any drive should work but you may need a drive caddy (mounting stuff). Depending on how old it is there may be a size limitation.
a drive cadyy just holds the harddrive in place inside your laptop but mostly all harddrives are 2.5 so hat shouldnt be a problem unless you have to break it to get to the harddrive like i did but i just bent it back in place.if you never changed a laptop harddrive before its not easy so be ready for a ride.