An old PC game about escaping a haunted house...?

Okay this was years ago so i can only remember little parts of it. So basically you were trapped in a haunted mansion with monsters and ghost and vampires etc.. specific characters were Frankenstien, Egor, a little kid, a three headed green thing and a scary ghost that was kind at one point but pulled a really scary face at another time. Every monster in the house could curse you. The aim was to find 12 keys around the house before midnight or you were trapped in the mansion forever. This was a fairly old game by the way. there was also some comic things in the house such as: dancing monsters in the basement (monster mash), records falling for a long time out the window (on the bottom floor) and the odd noise here and there (which were funny). I really wanna rememver this game, i know its a long description. Thanks.