Trying to install SolidWorks 2014. Getting a 1603 error code. "The Windows Installer for this product component did not run as expected: set_QuiteModeActions."

I’m running Windows 8.1 installed. There is easily sufficient disk and memory space and I have an NVIDIA GeForce GT640 graphics card with up to date drivers serving two displays.

MAchine has in the last fortnight been reformatted and reloaded, SW is the last piece of software I am now adding. So the registry and the machine in general is clean. The install is being done on an admin account, with Norton antivirus disabled.

I've been through everything i can find here on the net and am getting nowhere.

Relevant sections from the log files appear to be :

...

12:44:50    Error Status      157   0     "CustomAction set_QuiteModeActions returned actual error code 1603 (note this may not be 100% accurate if translation happened inside sandbox)"

...

12:44:54    Error Step  154   0     "** Install FAILED with code 1603"

12:45:09    Error Message     9     55200 "Dialog Shown: {0: Internal error: The Windows Installer for this product component did not run as expected: set_QuiteModeActions.: Contact Technical Support.}.  User selected: {1: 0}"

12:45:09    Info  Status      164   0     "Enter Final State called with install error = {0: ** Install FAILED with code 1603}.  InServer = 45278328, EnterFail = 45278208, status = 45278128"

...

Searching the forums and the web suggests that this is a VERY common problem. The advice is to uninstall Microsoft VSTA and then remove it from the registry.

Uninstall works fine, but the following keys are not present in my registry, so I am unable to remove them?

HKLM\SOFTWARE\Wow6432Node\Microsoft\VSTAHost
HKLM\SOFTWARE\Wow6432Node\Microsoft\VSTAHostConfig

The install only gets 1-2% into the install before failing.

Help please, this shouldn't be this difficult to install software!