while you are in the house, you just have to exit to neighbours screen, then click on the buldozer sign (on the top of the screen), then click on the house where u live in, it asks two questions, for the first one u choose YES, and secend one you choose NO.
then ur family will go to the family screen (ofcourse without your house onjects.) and now they have the money they paid to buy the house.
now you just gotta select the family again, and buy another house! thats all!

*im still looking for someone that has the original cds....