I think you all know that, since version 6.2, when you type the code for a smiley (e.g: " : p " for " ") the smiley appears directly, before you hit the [enter] key.

I find this feature really annoying and now it has been added to the version 7 !

Does someone could help me to deactivate that ?

You can use StuffPlug NG to disable this feature. You could also take a look at Auto-Emoticon-Completion-Disabler.

Both ways will only work on MSN Messenger 6.2.

There isn't much we can help you with because using MSN Messenger 7 is illegal if you are not a beta tester. You have 2 options. Live with it, or uninstall and go back to using 6.2 and StuffPlug-NG (which can remove the auto completion of emoticons, but of course you would need Messenger Plus! as well)

No one provide any further help

In fact I only use MSN 6.1 because of that feature in the 6.2

just use 6.2... get msg plus and spng and voila! you have a better version of 6.1