Microsoft removed the default System Properties page from the Windows 11 File Explorer.
You can check your PC's full specifications on Windows 11 by using System Settings, RUN Command, Command Prompt, and Task Manager.
To find specifications via System Settings, right-click the Start button, select Settings, go to System, and then click on About.
Using the RUN Command, enter dxdiag to display Motherboard details, BIOS version, Processor, and RAM, or use Command Prompt with systeminfo to view all installed components.