Issue with shutdown using task scheduler

I have several HP laptops running Windows 7 Professional that we would like to automatically shut down every evening.  In the past with our desktops, we have always used task scheduler to run a task using the "shutdown -s" command and then schedule the time and days we want the shutdown to happen.  It has worked flawlessly.  With these laptops they seem to shutdown at the end of the day, but then the next morning they are all back on again.  We have turned off "wake on LAN" in the BIOS but they still seem to be turned on the next morning.  We have turned off the wireless on the machines and they are all hard wired through our Ethernet network because we don't want to add extra clients to our wireless network traffic and the Ethernet ports were available below each machine on our computer tables.  Any suggestions on what we are missing?  Any help is greatly appreciated!