Hi, it looks like you stuck the Extension Calendar program in or something you installed did : MyCalendarPlanner 8.831.13.24175 (_itMembers_@free.mycalendarplanner.com) Try disabling that if that is not expected in Extensions/add-ons.

Give your self a scan : https://www.malwarebytes.com/

https://support.mozilla.org/en-US/kb/how-to-set-the-home-page

fyi : Firefox 52.9.0 is the last update for Vista as it is now EOL. All Future updates will be in the 60's and are for WIn 7. 8. 10

Please let us know if this solved your issue or if need further assistance.

REALTOROY said

My screen opens with an annoying Calendar Program, how do I get rid of this and have it go back to my Mail Page?

Are you sure you are referring to the web browser Firefox or to the Thunderbird email client?. If Thunderbird then this thread can be moved to Thunderbird section.

Pkshadow said

fyi : Firefox 52.9.0 is the last update for Vista as it is now EOL. All Future updates will be in the 60's and are for WIn 7. 8. 10

Almost EOL as 52.9.0esr was the last major update. There may still be one or more minor updates before September 5 when the Legacy Firefox 52 ESR will be made EOL.