Win 7 PC Restarting on Shutdown

[pnartg]

When I do a ShutDown from the Start Menu my (Lenovo Thinkstation E31 Windows 7 Pro 64 bit) PC automatically restarts.

N.B. that the that System Properties -> Advanced -> Startup and Recovery -> Automatically restart is UNchecked!

When I do the shutdown it goes all the way to lights-off/fan stopped, and then about a second later the lights come back on, the fan starts up and it reboots!

For it to go all the way to power-off and THEN restart doesn't there have to be something in the hardware to kick off a restart? (because the OS is no longer running at that point)? The only way I can shut off my PC now is to literally pull out the power cord during that one second of lights-out!

 

[SkyNetRising]

Check wake up settings in BIOS. Disable all, if any is enabled.

 

[pnartg]

Check wake up settings in BIOS. Disable all, if any is enabled.

I don't see anything like "Wake Up Settings" There is a Power tab in the BIOS and I have After Power Loss set to Power Off. There is a Power tab which has an Automatic Power On options for various devices, i.e., to set which devices can power up the PC remotely. But I don't have power-on capability with any external devices, e.g., the LAN. There is also a Start Up tab but all this appears to do is set which devices are booted from DURING startup - it doesn't seem to have anything to do with initiating a startup from a power-off status.

 

[pnartg]

I found another posting with an identical problem at http://www.tomshardware.com/forum/id-3256174/computer-starts-spontaneously-seconds-shutdown.html but I tried the solution in it, namely, doing a
powercfg -h off
from the command line but it didn't help. There was a mention of ErP in that thread - what it that?

I also went to the Control Panel options where it sets what the power button does. It was set to "sleep" (this is a desktop PC, not a laptop) so I set it to Shut Down. That didn't do anything either.