How do I remove someone from drop down box at sign in for messenger for Mac?

[shari]

Someone used my computer to enter messenger for mac to Chat....i would like to remove them from the drop down menu at the sign in box. How do I go about doing this??? Any help would be much appreciated

 

[Andon]

Someone used my computer to enter messenger for mac to Chat....i would like to remove them from the drop down menu at the sign in box. How do I go about doing this??? Any help would be much appreciated

I have the same problem i searched the net but can`t find anyone knows ?