If your Control Panel will not open in Windows 10/8/7, then this post will help you troubleshoot and fix the problem. It is quite possible that your computer may be infected with malware, the .cpl file may have become corrupted or damaged or the .cpl file association may have been broken. Before you commence troubleshooting the issue, remember to create a system restore point first.
Control Panel will not open
1] Run a full-scan with your antivirus software.
2] See if you can open Control Panel in Safe Mode or Clean Boot State. If you can, then some start-up is interfering with its operation. In Clean Boot State you will have to identify the offending program by disabling/enabling each of the start-ups.
3] Open File Explorer, type the following in the address bar and hit Enter to open your Syatem32 folder:
Search for *.cpl in this folder. The results will display all the Control panel applet files.
Click on appwiz.cpl and see if the main Control Panel window opens. If it does not, then from the WinX menu, open Run, type appwiz.cpl and hit Enter. Does the main Control Panel window open? If not, then it is quite possible that some .cpl file may have been damaged or got corrupted.
Click each one and see if the related Control Panel tool opens. If something does not, then it means that, that particular .cpl file has been corrupted or damaged.
Third-party software and hardware manufacturers often add Control Panel icons to provide an interface for setting configuration options for their products. If any of these 3rd-party Control panel icons has become damaged, it is best to delete it. But if it is some system .cpl file, then read on.
4] Run sfc /scannow to start the System File Checker. Restart your computer once the run is completed. This will replace corrupted system files, if any. Now see if you are able to open Control Panel now.
5] Check and set the File Association for Control Panel files and see if it helps. Now I am aware that you are unable to open Control panel, but if via the System32 folder as described above, you are able to click open inetcpl.cpl, then please do so. Then under its Programs tab, click on the Set associations button, under File Associations section to open the following window.
Here check if .cpl files are set to open with the default Windows Control Panel. If not set it so.
If you cannot do this, then simply download and apply this registry fix for .cpl files from DougKnox. The fix is for Windows XP, but should work for later versions too. Extract its contents and click on it to add it to your Windows Registry. If you don’t like the results, you can go back to the created system restore point.
Let us know if anything worked for you.