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In windows 7 you need to make some of the changes for speeding up your shutdown time is as follows:-
Click on Start.
Open Run command and type regedit.
In the regedit go at the following Location:


In the right pane, right click on WaitToKillServiceTimeout and click on Modify.
Type in a number between 2000-20000 (2-20 seconds) and click on OK.
Now Close regedit.
Restart your Pc.