I had the same problem same problem for a while, and didn't looked back to it for some months. Some days ago i decided to look again if i could fix it. The steps i took were a bit radical, but i must say it worked for me!
- Close every instanse of MSN and Messenger Plus!
- To make sure everything is shut down, press CTRL-ALT-DEL and look if you see any process named MsgPlus.exe, msmgs.exe or msnmsger.exe. If you see any of tohe, end their process until they are all gone.
- No go to the Control Panel --> Add/Remove Programs and un-install both Messenger Plus! and MSN Messenger (Plus! will ask you if you want to keep your settings during the un-install, you can select yes there).
- Reboot your PC.
- After rebooting, make sure there are no files left anymore in MSN's and Plus' folder ( C:\Program Files\MSN Messenger and C:\Program Files\Messenger Plus! 3 by default. If there are, delete those files.
- Now download MSN ( http://messenger.msn.com ) and install it.
- Download Messenger Plus! ( http://www.msgplus.net/download.php ) and install it to (reboot if you are asked too, but i think Plus! 3 never asks to reboot anymore).
- Download Screenshot Sender 3 ( http://www.msgplus.net/pluginsdb/down/pafiledb.php?action=file&id=71 ) and install it.
- Fully close MSN and start it again.
- SS3 should now work, if it still doesn't you could try to reboot your PC one more time.
A little note to people who might try this:
I do not garantee you at all this will work. It worked for me, but it could also have been because of some other things that i did on my PC between the time i last installed SS3 and my succesfull fix a couple of days ago. But if you don't want to wait until Dempsy releases his new build it wont heart to try this if you have the time. Remember Plus' settings will be save during un-install if you say so, but most of MSN's own settings are not.