Search notes:

msiexec.exe

msiexec.exe is the Windows installer (or uninstaller). 
msiexec /Option <Required Parameter> [Optional Parameter]

Uninstalling an application with its product code

msiexec /X{product-code}
The product code seems to be the GUID found under HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall.

See also

%SystemRoot%\Installer
The Windows Installer SDK has better documentation on the command line syntax.

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