There have been cases reported where for some users, Settings app in Windows 10 or the Change PC Settings option will not open in Windows 8.1 or Windows 8. Here are a few troubleshooting steps you may want to try and see if something helps you.

Settings app does not open in Windows 10

1] Open CMD and copy-paste the following:

powershell -ExecutionPolicy Unrestricted Add-AppxPackage -DisableDevelopmentMode -Register $Env:SystemRoot\ImmersiveControlPanel\AppxManifest.xml

Hit Enter. Restart your computer.

2] PC Settings is a Modern UI app, so check if you can open other Metro apps or not. If not, you may have to reset Windows Apps registry & file permissions to default values.

3] Take your mouse pointer to the bottom left corner, right-click to open the WinX menu and select Command Prompt (Admin). Type sfc /scannow to run the System File Checker. The System File Checker will check for corrupted files and replace them if any corruptions are found. You may be required to reboot your PC.

4] Boot Windows in Safe Mode and see if you can access PC Settings. If so great, use this opportunity to Refresh or Reset PC in Windows 8 or Reset in Windows 10.

5] Windows 8,1 users may open Control Panel and then All Control Panel Items > Recovery.

Click on the If you’re experiencing problems… link and see if PC Setting opens. If yes, nice, if not too bad.

6] Via the Control Panel, create a new User Account and see if you are able to access PC Settings.

7] See if you can access your System Restore Points. Open the WinX Menu, click on Run, type rstrui.exe and hit Enter to open the System Restore Manager. If you can try to revert your PC to a good old restore point.

8] Sometimes some third-party software has also been found to be the cause for the problem. You may want to uninstall such software and see if that helps. Troubleshooting in Clean Boot State may help.

9] If you are facing this problem after upgrading to Windows 8.1, then you may want to see this post on how to fix broken Change PC Settings link after upgrading to Windows 8.1.

10] Since you cannot open PC Settings, you will have to follow this procedure to Refresh or Reset PC. Press F8 while booting the system to go into Windows Recovery Menu. Click on Troubleshoot.

Click on Refresh your PC or Reset your PC to start the process. Make sure that you have backed up your data and files before starting this repair process.

Windows 10 users should boot into Advanced Startup Options, and secelectthe Refresh or Reset options.

See this if you get Broken Change PC Settings link after upgrading to Windows 8.1, and this one if Control Panel will not open. Windows 10 user? See Windows 10 Known Issues and how to fix them.