Okay, so I don't know how it happened but I have managed to "misplace" the stake for killing the vampires. I got it in chapter 1 when I did Korgan's quest, and somewhere between there and the castle, sewers, ice plane etc I dropped it. Can anyone tell me where to get another one, or a cheat code to insert a new one into the game. I really appreciate the help...

ummm...i got our stakes in chapter 3 from aran linvail's quests

You'll also find some in the locked chests in the graveyard underground labyrinths.

they also sell some in trademeet, once you've completed thier quests....

And you can buy some from the priest in on of those temples in the temple district (the one with the hovering sword)

Ermm... i've got a few stake (paranoid, i am) but how exactly do u use them?

Bodhi's lair is the only place with stakeable vamps. Well, no, that's a lie, there's one in the Asylum, too. You just kill the vamp, go to the room with its coffin, and click on said coffin.

Whoa, so easy???

Well, yes. The vampire's biggest weapons are its level drain abilities and its domination. Just make sure you have negative plane protection and chaotic commands on your best fighter and the vampire's just another monster (although one that attacks pretty quickly).