NOTE: Windows 10 users may want to see this post on how to remove the Folders from This PC in Windows 10.
Remove Folders from This PC in Windows 8.1
Close all your open File Explorer windows. From the Win+X menu, Run regedit to open the Windows Registry and navigate to the following registry key:
Here, you will see the following, each one corresponding to the Desktop or some personal folder: In my image you see the following key too – that is because I have added Recycle Bin to the This PC folder:
Backup the Registry Key
First, as a matter of precaution, identify the folder you do not wish to display, right-click on the corresponding registry key and click on Export. Name and save this .reg in a safe place. You will require it should you want to display this folder again in This PC folder.
Delete the Registry key
Now that you have identified the registry key corresponding to the folder you do not wish to have displayed and backed it up, right-click on it again and click on Delete. Click F5 to refresh the registry. Open This PC folder. The folder/s will not be displayed in your This PC folder! If you are running Windows 8.1 64-bit, then you will have to do one more thing. In the Registry, you will have to navigate to the following key and delete the same registry key/s from here too:
If you do not do this, then the folders will continue to be displayed in the Explorer dialog boxes like the Save, Save as and Open file windows.
Add personal folders back to This PC
If you wish to add back the Desktop folder or the personal folders, simply click on the corresponding .reg files which you had exported earlier and saved, and add its contents to your Windows Registry. Hope this helps.