my prius has no power

you need a new 12 volt battery. obviously, the auxiliary battery was not the problem.

 

I assume you mean the 12V battery, when you say you replaced the auxiliary battery. Check the battery cable connections to ensure they are tight, especially the negative cable where it bolts to the body. If you see any corrosion, this must be cleaned off.

If you are able to start the car using a boost, then there is nothing seriously wrong with your car.

Are you connecting the boost cables at the 12V battery itself?

 

or to the auxiliary battery?

 

That would still work even with the new battery not fully or properly connected. Please check Patrick's advice above.

 

1. Try to connect your boost cables at the 12V battery terminals, then see if you can make the Prius READY.
2. If #1 works, then you need to fully-charge the new 12V battery prior to use.
3. If #1 does not work, then connect the boost cables to the dedicated jumpstart terminal at the main relay/fuse box near the inverter. Confirm that you can make the Prius READY. Then shut the car down.
4. If you cannot find anything wrong with the 12V battery or its cables, then it is time for you to seek professional assistance.

 

when you say the engines not starting, can you put it in drive and move on the battery?

 

okay, follow pats advice above, either your neg battery cable is not tight to the chassis, or the battery needs charging.