Vodafone unregistered query?

hi guys i have be given a nice mobile phone using the vodafone network however when i switch the phone on it shows the message on the main screen "unregistered SIM" is there any way i can register this sim so i can top up the phone and use it straight away,i have other sims (o2 ,... show more hi guys
i have be given a nice mobile phone using the vodafone network however when i switch the phone on it shows the message on the main screen "unregistered SIM"
is there any way i can register this sim so i can top up the phone and use it straight away,i have other sims (o2 , t-mobile ) however these wont work and i dont have any unlock codes
so here are my questions
1) how do i register the sim
2) if i can use the other sims then what do i need to do
3) how do you find the number for the mobile
thanks guys for your help !
3 answers 3