Along with the mundane, this month's Windows Update for Vista includes some prerequisites for Vista SP1.
Speaking of Windows Vista SP1, the final two of three prerequisite
updates needed to install Windows Vista SP1 will also be hitting
Windows Update. KB937287 which is the servicing stack update and
KB938371 which is a multi-component update are both required before
installing Windows Vista SP1. KB938371 will not be offered to Windows
Vista Enterprise and Windows Vista Ultimate systems until KB935509, the
first prerequisite in the series of three, has been installed. Both of
the Windows Vista SP1 prerequisites are marked "Important" and will
install automatically if you have Window Updates set to the recommended
Recommended configuration = update automatically, if you don't read Microsoft-speak.