Go back in the mansion and use the key on the door underneath the staircase

He’ll talk to you and you’ll be finish with the World of Warcraft Gold quest in the game. Summing it up:

1) – Talk to Veronica outside of the Draynor Mansion.

2) – Get a fish food in the second floor of the mansion.

3) – Then get a poison in the west room of the first floor. Use the poison with the fish food.

4) – Go all the way to the east room to get a spade.

5) – Head outside of that room and west until you find a cabbage field.

6) – Next to it is a pile of compost; dig in it with the spade to get a key.

7) – Now go south until you find a fountain. Use the fish food on the fountain. All the fishes in the fountain will die.

8) – Search in there for a pressure gauge.

9) – Go back in the mansion and use the key on the door underneath the staircase.

10) – Get the rubber tubing.

11) – Then go all the way west again and down the ladder.

12) – Now follow these instructions to get the oil can.

13) – Grab the oil can and head back up the ladder.

14) – Go up the Staircase.

15) – Then climb the ladder behind you.

16) – Talk to Professor Oddenstein twice.

17) – He’ll operate the machine and Ernest will return back to human.