I just tested this out, and it works (for me at least, can someone smarter than me confirm it).
1. Create a new file in notepad, with the following in it:
code:
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Patchou\MsgPlus2\Nobody\Preferences]
"EnableLogging"=dword:00000000
save the file as run.reg and then run it.
2. Go to Start > Run > Type 'msconfig'
3. Browse to HKEY_CURRENT_USER\Software\Patchou\MsgPlus2\
4. Delete the folders for the people who's conversations are still being logged.