We cannot stress this enough: if you're still on Windows 7, you should absolutely upgrade to Windows 10 by January 14th. After the 14th, Microsoft will no longer support Windows 7. It will be fine in the beginning but as more security vulnerabilities get discovered, the more likely your computer on Windows 7 will be at risk.
You can purchase Windows 10 for $139, but you can still upgrade it for free for the time being. Here's a CNET article on how you can do so: https://www.cnet.com/how-to/upgrade-to-windows-10-free-heres-how/