The trial version limits the number of days you can use. It allows you to see how Petroleum Office works during 15 days trial period.
To update an existing copy of Petroleum Office, just install the new version over the existing copy. It’s that simple.
Petroleum Office installation requires Microsoft Excel 2010, 2013, 2016 or 2019 (including Office 365) for Windows and .NET Framework 4.7.2
Most likely you need to run the setup file as Administrator. Right-click on setup file and choose menu run as administrator. Also check Articles sections for more suggestions.