Hey there,
Have you tried reinstalling MSN and/or Plus! to see if this resolves your problem?
Also,
Make sure that Plus! is still in your startup list, a program or piece of software may be removing plus! from starting when you load your computer. You can check your startup list by typing msconfig in the run dialog and clicking startup.
There you can check for two entries both named MsgPlus. If they are not there, check to see what software could possibly be uninstalling these startup entries, disable it then reinstall Plus! to make sure they are restored.
If Plus! is actually starting and integrating with MSN/WM and the Plus! logo is not appearing in conversation windows, then a bug report will need to be posted, but it does seem that your plus! is some how been disabled.
Oh, one more thing, make sure there is no one who is using your computer that is uninstalling it
- was the only thing i didnt check when my Plus! kept going missing last month
Hope that helps, Tah,
Hah