can I tell if someone is switching?

off the pc at the power source rather than shutting down properly

The Outcaste2012-08-01T04:42:53Z

Favorite Answer

Administrative Tools | Event Viewer
Windows Logs | System Log
Highlight the System log in the left pane
Click Action | Filter Current log
Select Eventlog and eventlog for Source, and event ID 6008

This will show an entry like this one with the date and time the power was removed (or the system crashed, could be either one):

Log Name: System
Source: EventLog
Date: 8/1/2012 4:17:39 AM
Event ID: 6008
Task Category: None
Level: Error
Keywords: Classic
User: N/A
Computer: Win7Home
Description:
The previous system shutdown at 4:13:57 AM on ‎8/‎1/‎2012 was unexpected.