try this one.may be this can help.
You might have a corrupt file in your Yahoo! Messenger directory. To fix the problem, you must manually delete the Messenger directory on your C: drive (default), then reinstall the Yahoo! Messenger application.
To delete the directory:
Close the Yahoo! Messenger application if you currently have it running. Make sure all instances of Internet Explorer are closed. Go to your desktop and double-click "My Computer." Click the "C:" drive. Go to: C:\Program Files\Yahoo! Highlight the Yahoo! Messenger folder and press the Delete key on your keyboard. (All archives will be deleted if they are not copied. Please see below.) To install:
Close all running applications except for your Internet browser. Visit the Yahoo! Messenger home page. Click the "Download Now" button. To copy your complete Message Archive:
Close Yahoo! Messenger (if it is currently running). Go to your Desktop and double-click "My Computer." Select the "C:" drive. Go to: C:\Program Files\Yahoo!\Messenger\Profiles. Your "Profiles" folder contains your complete Message Archive. Copy it to the same location on another computer if you wish to view it elsewhere. Note: If you copy this folder to another computer, your complete Message Archive will be copied, overriding the Message Archive on the computer to which you are copying.http://help.yahoo.com/l/us/yahoo/messenger/messenger8/messenger/index.html
how can i recover my pass word of my yahoo messenger since i also forgot my secret answer of the 2...
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how can i recover my pass word of my yahoo messenger since i also forgot my secret answer of the 2 question