In live chess.
click on Settings(under the chat window)----> Play-----> uncheck multiplay
Probably the best idea is to turn off Multiplay. You do this by clicking Settings, then under the Play tab you will see the Multiplay check-box. Uncheck that (as indicated by the previous poster).
You can also limit incoming challenges on the Play tab as well. You might select Challenges from to be Nobody.
A couple of options that you can mix and match, there.
Is there any way how to disable option of playing multiple live games? I keep receiving challanges while playing which is most disturbing. Once I even accepted a challange by accident and lost on time in the second game.