How to Deal with a friend Who Constantly Talks about Another Friend?

Sweety...its natural phenomenon....look two intentions of ur friend would be...1 she wanted u to be more fair and close to her by giving u example of other friend...may it is hypothetical just to annoy u and realise ur faults at her.....2 she wants to degrade u to keep u at level down from herself.... or may be she would b psycho too.....So i would recommend you to start ignoring her for few days in this way she would miss ur company and start thinking and praising you ,would forget last friend and would get lesson without you!