Be relax if you have seen 0xc000021awindows problem occurs, please read the recommended solutions below.
To uninstall a program from Windows 8:
1. When in the "Start" screen, start typing "Control Panel".
2. Click on the "Control Panel" from the Apps search results. In the opened window select "Programs and Features".
3. In the Programs and Features window select the program you want to uninstall and click on the "Uninstall" button.
Process Explorer is a system tool from Microsoft and works on Windows 7, an advanced tool which can show processes name, program data, description, image, processer name, etc. Have a try with Process Explorer; for example, use it to kill a program process.
1.Download Process Explorer.
2.Open process explorer, the main window looks like below, there are 2 parts, left side is processes list, and the details are listed on right side.
3.You can check system information by clicking View > System Information.
4.You can kill process by right click on related process name, select Kill Process.