We suddently lost our dog, that has been with us for almost 10 years. Is there any puja or mantra that I could do, and also can a dog attain liberation.I have always offered my pet ,a part of the prasad from my worship, will this in anyway help the next birth of the dog.

Swamiji says:
It would be appropriate to chant Mahamrityunjaya Mantra.
Animals do not attain liberation. They become reborn in another form - possibly human.
It is appropriate to offer prayers and to perform pujas for the upliftment of that soul.

I have seen the video on Satyanarayan vrat ( http://www.shreemaa.org/drupal/node/721) but it doesnt give the instruction on how to perform the puja. Is it possible to get the instruction on how to perform the Satyanarayan puja?

Swamiji says: The actual puja is the vow to speak and act in truth.The Vishnu puja in the beginning of the book is sufficient to ratify that sankalpa.Then read the Vrat, the story of other people who observed the vow.