I live in New Jersey... My mother passed away June 2013, my heart is still broken. I have an older sister and brother. At first my sister said my mom had a "WILL" and now she said she didn't. According to her, my brother and her had "POWER OF ATTORNEY" for any medical decision. That is why she was DNR and that was upsetting enough. Now my sister and her husband want to sell the house to get their 1/3. My moms house is paid. No mortgage. We pay the taxes and all the utilities. Can she do this? What can I do to stop it? I don't want to lose my mom house. We grew up there.

Are you living in that house?
Who is the 'we' paying the taxes?
You can contact the probate court to see who is executor, and where the settlement of the estate stands.
Without a will, your mother died intestate, so probate will take a bit longer. You and your 2 siblings should each get a third of the estate. This means dividing up the house, regardless of paying taxes and utilities. That is something you have to negotiate amongst yourselves. They will say it was what you owed for living there, if you lived there.
If you think there was a will, it is up to you to find it, perhaps on file with a local lawyer.
Dividing the house can take any form you all agree on, such as you buying their shares out. If you can't afford that, and/or if you can't come to an agreement, it will have to be sold.

Sorry for your loss.

As you may know, the POA is now of no effect. If she wants to sell the house, she will have to apply to the probate court to be appointed personal representative. If there is actually no will, either of you could so apply, but, before the house could be sold, a probate application will have to be filed.

Each of the three siblings will probably inherit 1/3 interest in the house and other assets in your mother's estate. It would not be a good idea to give each of you a 1/3 undivided interest, so yes, it will probably have to be sold so that the proceeds can be divided between you. If you, or anyone else, wants the house, he or she can buy it. You will probably be given credit toward the purchase with your 1/3 interest, but you will have to figure some way to come up with the difference. One way to consider would be obtaining mortgage financing.