Well I know, amongst hundreds of bugs that you face if you are an unfortunate user of Windows Vista, shut down time is a real annoying part. It takes unimaginably more time to shut a darn computer down. So here is a registry tweak that can make the job fairly quick.

Step 1: Open the Registry Editor by going to the Start Menu, and typing regedit in the Search bar and then pressing Enter.

Step 2: Within the registry editor navigate to the key "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control"

Step 3: Now, Edit the "WaitToKillServiceTimeout"="20000" by right clicking on the key and selecting Modify.

The Default setting is at 20000 milliseconds (20 seconds).