Hi, lorretta,they just need bleeding, on one side of the radiator there is a bleed screw (at the top) just slacken it of slightly and release the air, put a cup or container under the bleed screw to catch the drop of water that comes out after the air has been released, when you see the water tighten up the scew. You will have to do this to all the radiators in the house starting with the one nearest the boiler and working away from it, you can by a bleed key from your local do-it yourself shop or maybe your neihbour can lend you one, hope this helps let me know how you get on.
Garry, November 2008