my clio turns but no spark at plugs anyone who can help?

i just got the clio the other day and was told it was just back box so when drive home it run out of petrol put £10 in light when out tryed starting it it started but cut out when u put foot down . ended up with flat battary got it towed home and so changed battary , now the car turns but no spark at plugs ,plugs r ok. but it has not got a imobiliser key so it must of been turned off as the keys she give me were cuts. but as i took battary off would this of reset it. anyone help thanks