Office 2007 reached its 'End of life' date on 10th October 2017. It means that although you can continue to use the software, Microsoft is no longer providing updates, bug fixes, or vulnerability fixes for that version of Office.
Your choices are:-
Continue as you are, but in an unprotected state.
Migrate to a newer version of Office - Microsoft wants everyone to use Office 365.
Use another application suite.
Take a look at Open Office it's free, and will be fully compatible with all your MS Office files. You should however, be aware that it doesn't have an email client although there are plenty of third-party options from which to choose.