Hello

I have a Fiesta Zetec 1.25 W Reg.
Came to start the car today and put the key into the ignition and turned the key and the car just makes a fast ticking sound and will not start. I used it last week so the battery shouldn't be flat but when i lock the car the motors which lock the door sound like they have hardly got any power.
Do you think it could be a flat battery or Starter Motor?