I would review your Resource Manager to see what processes are running in the background. Typically the long delay is caused by the programs closing down in the background.
Also, you can look at change WaitToKillServiceTimeout to 1,000 (or 5,000 or so if you receive hang ups), which will help speed up the shutdown (a tweak used for SSD's)
Type Regedit into the Start Menu Box;
Select the file path: “HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control”
The last file is WaitToKillServiceTimeout.
Right Click and select Modify to change the value from 12000 to 1000.