Battery dead?

There is a charging point under the hood.
Section 5 of the 2007 owners manual shows how to jump start in the front.
http://priuschat.com/forums/attachm...ners-manual-pdfs-2007-prius-owners-manual.pdf
(about page 371 of the PDF, page 361 in the manual)

 

To open the main relay/fuse box near the inverter, press hard on the latch in front of the box, then pivot the cover up. Then you'll see a red plastic cover over the dedicated positive jumpstart terminal.

If you need to open the hatch manually, then read on.

Enter the car via one of the unlocked front doors. Note the inside door lock handle that shows red, indicating the door is unlocked.

Reach back to the back door, and manually unlock the door, looking for the door lock handle and moving it so that it also shows red. Now the door is unlocked.

Then open the back door, lower the rear seat back, and crawl into the hatch area. Remove the folding hatch floor bottom. Remove the small access panel at the rear of the black plastic tray over the spare tire.

Find the manual hatch release latch which is a little shiny metal lever, and open the hatch.

Remove the hatch floor cover over the 12V battery, in the right rear corner. Now you have access to the battery, and can replace it or do whatever you need to do.

 

Open the driver's door manually.
Pop the hood.
Expose the jump point as described.
Hook up a charger.
Try to charge the battery or start the car.
Drive it to the dealer for a new battery. Don't turn the car off.
Buy a battery.
At 5 years you are past due.