There are several discussion threads on Google and other forums discussing difficulties when reinstalling Google Chrome. You get the standard online ActiveX installer or the standalone installer, but neither will start properly, reporting 'Installer was unable to start'
I tried manually deleting various Google folders from Program Files, Program Files (x86), Common Files and in the registry; HKLM\Software\Google and HKCU\Software\Google.
Still got the error about Google Update installation failing initialization.
Until ... I deleted the HKLM\Software\Wow6432Node\Google key as well. That cleared the fault up and the installer was able to run successfully.