Generic way of brute force installing a .MSU package in Vista or Server 2008

Suppose you receive the dreaded This update does not apply to this system. message when attempting to install a .MSU package, but you know for a fact that it really does apply.

You can, to a certain extent, short circuit the update process by doing the following:

Suppose you are trying to install a patch from KB article 667668 (currently not a valid KB) for a 32-bit install:
expand -F:* Windows6.0-KB667668-x86.msu %temp%\kb667668\

start /w %SystemRoot%\system32\pkgmgr.exe /ip /m:%temp%\kb667668\Windows6.0-KB667668-x86.cab

Thanks go to Ottó Horváth for the tip, slightly modified.

You can also uninstall updates this way too, by changing the /ip to /up.

Update: One thing I forgot to mention, is that if you need to install multiple updates this way, you will need to use a different directory for each update, which is sort of hinted at by my use of \kb667668\. It is documented why here in KB 932224.