Is there a really-really-really-don't-reboot parameter for msiexec?

Solution 1:

The strongest "don't reboot" option in Windows is to temporarily remove the "Shut down the system" and "Force shutdown from a remote system" privileges from "Administrators" and "Users", using secpol.msc. In this way, it will be enforced by Windows, regardless of how the particular installer or MSI package is written.

Note: User privilege changes apply only when you log in.

Note: You may have to remove the Users group as well, since interactive logons automatically belong to this group.

Note: In some cases, it might be better to use the "Token" tab in Process Hacker to directly remove these privileges (SeShutdownPrivilege and SeRemoteShutdownPrivilege) from the program, instead of doing it system-wide.

Solution 2:

REBOOT=ReallySuppress is the best I know of, but if you're having trouble uninstalling Office 2010 you might want to follow the advice over here:

We recommend that you follow the provided methods in this article in order. However, if you have previously tried one of the methods to remove Office and it has failed, you can jump to another method quickly from this list:

Method 1: Uninstall Microsoft Office 2010 suites from Control Panel
Method 2: Uninstall Microsoft Office 2010 suites with Microsoft Fix it
Method 3: Uninstall Microsoft Office 2010 suites with the Program Install and Uninstall troubleshooter
Method 4: Remove Microsoft Office 2010 suites manually