Ho I need to wait for 5-6 minutes to make my laptop shutdown because I am using Microsoft Vista on my Laptop!!!. I googled about this and I found some information to avert this problem.
Edit some information in the Regedit can increase the speed of shutdown in Windows Vista.
Start Run (Windows Key +R) program and type regedit and hit enter.
Navigate through HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control
On the right pane Modify the WaitToKillServiceTimeout string by right clicking on the string. The value will be 20000, make it 5000 instead. This worked well for me.