In light of the fact this is a scripting board, and because a discussion on kixforms reminded me of this, thought I would share some information on the typelib viewer installer switches. The following switches can be used for the setup:

/SP-
Disables the This will install... Do you wish to continue? prompt at the beginning of Setup
/SILENT, /VERYSILENT
Instructs Setup to be silent or very silent. When Setup is silent the wizard and the background window are not displayed but the installation progress window is. When a setup is very silent this installation progress window is not displayed. Everything else is normal so for example error messages during installation are displayed and the startup prompt is (if you haven't disabled it with the '/SP-' command line option explained above). If a restart is necessary and the '/NORESTART' command isn't used (see below) and Setup is silent, it will display a Reboot now? message box. If it's very silent it will reboot without asking.
/SUPPRESSMSGBOXES
Instructs Setup to suppress message boxes. Only has an effect when combined with '/SILENT' and '/VERYSILENT'. The default response in situations where there's a choice is: -Yes in a 'Keep newer file?' situation. -No in a 'File exists, confirm overwrite.' situation. -Abort in Abort/Retry situations. -Cancel in Retry/Cancel situations. -Yes (=continue) in a DiskSpaceWarning/DirExists/DirDoesntExist/NoUninstallWarning/ExitSetupMessage/ConfirmUninstall situation.
/LOG
Causes Setup to create a log file in the user's TEMP directory detailing file installation and actions taken during the installation process. This can be a helpful debugging aid. For example, if you suspect a file isn't being replaced when you believe it should be (or vice versa), the log file will tell you if the file was really skipped, and why. The log file is created with a unique name based on the current date. (It will not overwrite or append to existing files.)
/LOG="filename"
Same as /LOG, except it allows you to specify a fixed path/filename to use for the log file. If a file with the specified name already exists it will be overwritten. If the file cannot be created, Setup will abort with an error message.
/NOCANCEL
Prevents the user from cancelling during the installation process, by disabling the Cancel button and ignoring clicks on the close button. Useful along with '/SILENT' or '/VERYSILENT'.
/NORESTART
Instructs Setup not to reboot even if it's necessary.
/RESTARTEXITCODE=exit code
Specifies the custom exit code that Setup is to return when a restart is needed. Useful along with '/NORESTART'.
/DIR="x:\dirname"
Overrides the default directory name displayed on the Select Destination Location wizard page. A fully qualified pathname must be specified.
/GROUP="folder name"
Overrides the default folder name displayed on the Select Start Menu Folder wizard page. If the [Setup] section directive DisableProgramGroupPage was set to yes, this command line parameter is ignored.

Here is a list of exit codes that may be returned (if a restart is needed you can set your own code as indicated above):

0 Setup was successfully run to completion.
1 Setup failed to initialize.
2 The user clicked Cancel in the wizard before the actual installation started, or chose "No" on the opening "This will install..." message box.
3 A fatal error occurred while preparing to move to the next installation phase (for example, from displaying the pre-installation wizard pages to the actual installation process). This should never happen except under the most unusual of circumstances.
4 A fatal error occurred during the actual installation process.
Note: Errors that cause an Abort-Retry-Ignore box to be displayed are not fatal errors. If the user chooses Abort at such a message box, exit code 5 will be returned.
5 The user clicked Cancel during the actual installation process, or chose Abort at an Abort-Retry-Ignore box.