hiya ! whatever you do dont join in with her and yell at her to stop she may just see this as you joining in whatever it is she is barking at , you need to ignore her dont even look at her. when she realises its having no response from you she may stop . you could try putting her in another room again no talking or looking at her just pick her up put her in another room and only let her out when she is quiet if she starts again put her back perserverance (if thats how you spell it) is the key . she could be barking at something you cant hear dogs having much better hearing than us its a possability . or you can try distracting her with a toy or just leading her away into the garden but usually the more attention you give to bad behaviour the worse it gets . let us know how you get on , you could just get some ear plugs lol.