I have a similar problem:
I cannot open any IM windows like i double click on someone or go to "Start a conversation with...." option, but no matter what i do i can't open an IM window.
I have tried numorous versions of MSN Messenger (6 --->7 ) but non of them work.
I then discovered that this only happens with my USERNAME!!!!
eg, if a mate of mine logs in MSN Messenger on my computer, it is completely normal for him....
I even get the toasts when people send me messages but no IM window opens!!
MSGPLUS even logs my chats...
I have tried uninstalling --> reinstalling MSGPLUS but nothing works...
i just want my msn messenger back!
I'm currently using the crappy windows messenger.