I have have had MSN Messenger and MSN Messenger Live Plus installed and working on my windows XP for several months now.  I recently installed some windows patches, and now I get the "Messenger Plus - Installation Altered" message.  "Messenger Plus! has not been installed properly on this system.  Please download and install the setup package of this program." When I click okay on this message, internet explorer opens an goes to the message plus web site.

This problem occurs on 2 of 4 accounts on the PC.

All accounts are administrator accounts.

The problem occurs immediately after login, even though automatic launching of messenger is disabled.

If I close explorer and launch messenger from the accounts reporting the error, it works properly.

I have uninstalled and reinstalled messenger and messenger plus many, many times with the same result.

Any ideas on how to correct this?

Uninstall messenger plus and msn messenger.
Then delete their folders in programfiles.
Then install them again.

Try it