When Microsoft stop supporting Windows 7 in January next year there will be no more security updates / fixes which means continuing to use this operating system for anything that involves your personal information, in particular your online banking or for buying and selling will be an increasingly risky proposition. The only way forward will be to upgrade your system to Windows 10.
Fortunately, most computers currently running Windows 7, 8 or 8.1 should be capable of upgrading to Windows 10 and running it comfortably – a few might need a bit more memory (RAM) adding. Computers running older operating systems going back as far as Windows XP and Vista may also be suitable, depending on their specification.