Try this:
1. turn off water at mains stop tap.
2. open all cold taps until water ceases to flow.
3. close every tap approx. two-thirds, then turn on water at stop tap.
4. adjust taps to get a small, even flow of water.
5. start at the bottom/lowest floor of house, and turn every tap until they are all half open, then all three-quarters open.
6. this should allow air to spurt out of the taps.
7. when water is flowing without spurting of air, turn off every tap in rotation, until only a dribble flows out.
8. close all taps.
Sorry I was so long at getting back; my computer is playing up.