The “remove a stake from a vampire’s heart to revive him” bit was invented by Hollywood, in order to enable them to do a sequel after the main character got wasted – despite their attempts to make the vampire hunter the hero, the audience always knew who the REAL main character was!.
Here’s the lowdown (mostly drawn from Horror! by Drake Douglas):
To kill a vampire, you must first locate his coffin, which is a chore in its own right. The vampire has plenty of practice, not to mention motivation, to keep it well concealed. He may also have decoys or spares scattered about.
Once found, you have to drive a wooden stake through his heart. Some legends say that the stake must be made of poplar wood, being the same wood as used in the cross on which Crist was crucified (which is why the terrified poplar leaves tremble, by the way), but I tend to doubt this as poplar wood is fairly soft.
You don’t use a wooden mallet to drive the stake, by the way. Instead, you drive it in using the back of a shovel – specifically, a sexton’s spade (that is, a spade used to dig graves). Make sure that you have ground the edge of the spade to a razor edge – we’ll get to why in a moment.
The key thing about driving the stake is that you must drive it in with one blow. If you hit it a second time, you will restore the vampire to full strength and you will probably die. Think about how awkward this is: you are driving the stake with the back of a shovel, and you only get one shot.
Once the stake is in place, you use the razor edge of the spade to strike off the vampire’s head. Again, you only get one blow to do this.
You then stuff the vampire’s mouth full of garlic.
If you have done everything correctly, the vampire will now crumble into dust, thus making it impossible to revive him by removing the stake.
It is also possible to destroy a vampire by exposing him to sunlight, or by burning his body in his coffin. However, the latter method is chancy, because the vampire may escape the pyre in the form of an insect.
Some have held that a silver bullet (usually used to dispatch werewolves) can also kill a vampire, but that exposure to the rays of the moon will bring him back to life (or perhaps “back to undeath” would be the correct phrase). The “unstaking” concept may be a corruption of this concept.
By the time you have gotten through all of this, the sun has probably gone down and the vampire’s buddies (or girlfriend) is probably standing right behind you and is pretty pissed off…