This software allows users to log system events, power events, user activity, screen saver and monitor power to track computer usage for billing purposes.

Besides capturing these events, SimpleActivityLogger has a small GUI application that lets the user view the event log and append user events to it. With this feature, the user can track their computer usage and even use the information for billing and timesheet purposes. Additionally, it is useful for monitoring the usage of shared computers.
While SimpleActivityLogger does not aim to be a covert 'spy' program and makes no effort to disguise itself, it is compatible with Windows Vista onwards and Windows Server 2008 onwards. It has been explicitly tested with various versions of Windows 7, Windows 8.1, and Windows 10, including both 32-bit and 64-bit variants in the case of Win7 and Win10.
SimpleActivityLogger requires local administrator privileges during installation but works seamlessly with Standard (limited) User accounts afterward. Overall, SimpleActivityLogger is an excellent software with a powerful yet straightforward function that is very useful to those who want to monitor their computer usage.
Version 3.0.0:
Now logs to the Windows Event Log rather than a text file.
Many new events are logged.
Complete overhaul of the GUI application.
Much improved offline help.
Various bug fixes and improvements.
Version 2.3.0:
Can now log the powering off and powering on of the primary monitor (requires Windows Vista or later).
Updated the application icon.
Version 2.2.0:
Log user's full name instead of username.
Various improvements and bug fixes.
See https://coruscant.co.uk/2017/05/simpleactivitylogger-v2-2-0-released/
Version 2.1.1: Can now log Fast User Switching, better timestamp support including custom formatters, can now suppress header lines, various bug fixes.