Windows 7 has a tencancy to automatically install a few updates right after a fresh
install (regardless of its default settings). You can suppress this behavior by
editing the value specified for the variable <ProtectYourPC> in the unattend.xml for
Windows 7 task sequences for Windows 7 deplyoments. Here are the possible values:
1 - Specifies the recommended level of protection for your computer.
2 - Specifies that only updates are installed.
3 - Specifies that automatic protection is disabled.
NOTE: Option "3" is usually the best choice if you already have an internal WSUS.