There is no key. You have to get the Game Guide to Twisted Wizard by chasing Manny to the school. Bring it back and give it to Greg. After you give the guide to Greg, he beats the game, then you have to beat it. Then you return the CD to Rowley and he gives you his Joshie Club card. Use it to open the laundry room.
you turn off the power in the laundry room.
Use it to open the laundry room door at Gregs house.
you open the laundry room door with it in Greg's house.
Once you get the Joshie Card, you can put it in the slot to open the Laundry Room.
in the laundry room
You turn off the elecricity in his room from the laundry room
You can't open the door. It has no use for completing Wimpy Wonderland
You have to get rid of the snow in front of it. Its pretty obvious.
Mannys room
Get the Joshie card from Rowley and open the laundry inside the house with it. Open the power thing and flick the switch for Rodrick's room. He will come out, leaving his room unlocked.
You have to get the Joshie Club Membership Card from Rowely then use it on the door.
He's waiting for you. Use the Joshie card to open the laundry room door and turn off the power to Rodrick's room in the basement.