The primary reason for the problem you are seeing occurs if you have a popup/ad blocking feature enabled…
- If you are using a tool bar (yahoo, google, etc.) and have the popup blocker enabled, you will need to disable it until you have completed composing or replying to your message. The alternative is to either list the webmail page as a 'safe' site or disable the popup blocker for the webmail page.
- If you are using Norton Internet Security, you will need to disable the popup/ad blocking feature... The following article found on the Symantec Website may assist you in doing this...