When turning off your computer from the Start menu, Windows 7 may attempt to install or finalize updates during shut down. Since certain updates can take a while to finish, turn off your computer normally by using the Shut Down option present on the CTRL-ALT-DEL screen. Further, you can prevent the Start menu Shut Down button itself from applying updates either by configuring the Windows Update policy settings or by completely disabling Windows Update.
Press Ctrl-Alt-Del while on the Windows 7 desktop to open the CTRL-ALT-DEL screen. Click the arrow-shaped icon on the red-colored button, and then select Shut down to turn off your computer normally.
Windows 7 may still attempt to install updates the next time you turn off your computer via the Start menu. As a permanent measure, disable the Start menu Shut Down button from applying updates by configuring Windows Update.
Local Group Policy Editor
Open the Start menu, type gpedit.msc, and then press the Enter key on your keyboard to open the Local Group Policy Editor.
Double-click the Administrative Templates option under User Configuration, and then click on Windows Components. On the right-pane, double-click Windows Update.
Double-click the policy setting labeled Do not adjust default option to 'Install Updates and Shut-Down'.
Click the radio-button next to Enabled. By default, the policy setting is set to Not Configured.
To turn back on Shut Down button updates at a later time, select Not Configured.
Click Apply, and then click OK to save the changes.
Open the Start menu, and then use the Shut Down button to turn off Windows 7 normally. You can still use the Install Updates and Shut-Down option that shows up after clicking the arrow-shaped icon if you want to install the updates.
Disable Windows Update
Type Windows Update into the Start menu, and then press the Enter key to open Windows Update.
Click the Change Settings option.
Open the pull-down menu under Important Updates, and then select Never Check for Updates (Not Recommended). Click OK to apply the changes.
The Start menu Shut Down button no longer applies updates. You also don't have an Install Updates and Shut-Down option unlike when using the Local Group Policy Editor to disable Shut Down button updates.
Disabling Windows Update prevents Windows 7 from receiving the latest security fixes and feature updates. To turn back on Windows Update, get to the Windows Update Settings window, and then select either Install Updates Automatically, Download Updates but let me choose whether to install them, or Check for updates but let me choose whether to download and install them.