How do you I remove and install a hard drive in a Dell computer?

Ideally if you don't already know, you shouldn't be doing it. Especially if you don't know about anti-static precautions. For a desktop: Ground yourself against a radiator or any earthed metal (just hold it for a few seconds) to remove any static charge you may be carrying. Unplug the power supply, open the case of the PC (may require removal of screws or undoing clips depending on the model of PC). Find the hard drive which needs replacing, it should look pretty much same as the one you have to replace it with. If there is more than one hard drive present, then you'll have to check which one needs removing before continuing. Unplug the power connector and the data cable from the back of the old hard drive. Remove the hard drive (if in a caddy you will need to swap the caddy over, which may require removal of some screws as well). Put the new hard drive in (also using the caddy if one was present). Plug the 2 cables back into the hard drive. Put the case back on. Job done!