Hi Jireh,
Welcome to Microsoft Community.
I'm Hahn and I'm here to help you with your concern.
Lumia 520 runs on the Windows Phone operating system, and Microsoft has discontinued support for Windows Phone. This means that there are no more official updates or upgrades available for this device. Support options for Nokia, Lumia, and feature phone devices - Microsoft Support
To update your Lumia 520 using a PC, you'll need to use the Windows Device Recovery Tool. Windows Phone Device Recovery - Microsoft Community
Please note that because Microsoft has discontinued support for Windows Phone, you may not have access to the latest apps and updates. If the above doesn't work, you can try third-party upgrade options on the web.
I hope this helps. If there is anything not clear, please do not hesitate to let me know.
Your Sincerely
Hahn - MSFT | Microsoft Community Support Specialist