Thinkpad 201X Laptop Shuts Down with 2 External Monitors


TS Rookie
I've set up the laptop to work with 2 external ThinkVision L171 monitors, using Windows 7 Professional. One is connected via the VGA monitor port on the laptop; the other is connected via VGA to a Lenovo/DisplayLink USB 2.0 Port Replicator (model VDK8736 -- with drivers updated).

Both monitors are working well and available when the laptop lid is closed. The issue is that after the screen saver period completes, the laptop powers down completely. I'd like it to just shut off the screen and resume on mouse movement.

The laptop is used with external monitors when it's plugged in -- and the power settings are:
Balanced profile
Display turns off after 2 hours
Screensaver starts after 10 minutes
Computer goes to sleep - Never
Hard disk off - never
Internet Explorer: Javascript Timer Frequency - Maximum
Desktop background settings : available
Wireless Adapter Settings: Max Performance
Sleep - Never. Hybrid Sleep: Off Hibernate After: Never Allow Wake Timers: Disable
USB Selective Suspend: Disabled
Intel Graphics Power Plan: Balanced
Power Buttons & Lid: Lid closed - Do nothing; Power Button - Sleep; Sleep Button - Sleep
PCI Express - Moderate Power
Multimedia - When sharing media - prevent idling to sleep; When playing video - Optimize video quality

Does anyone know why this is happening and a way to prevent it?