If you are having an issue upgrading/installing/running Messenger 6.0, please follow the directions below:
Make sure to exit Messenger completely. If you don't, the uninstall will fail.
Click the Start button.
Select Settings and then Control Panel.
Double-click Add/Remove Programs.
Select Yahoo! Messenger and click the Remove button.
Click the Next button and then the Finished button.
The next step is to install:
Close all running programs except for your Internet browser.
Please download the installation file to your desktop.
Download the file to your Desktop and then double-click the ymsgrins.exe file to begin the installation. This should solve the issue.