Despite my initial enthusiasm I have been forced to ditch both "PC On/Off" and "PC Usage Viewer" because on my current system -due to an installed rollback application which is actively running- the only data detected/logged by both applications were the snapshots creation timestamps
... So in a month log my system appeared to be up for barely 10 minutes!
The fact that both apps are rendered basically useless by the coexistence of a system rollback program should be probably mentioned somewhere in the app description... (webfork's input in this respect would be certainly beneficial).
Fortunately, dmg's AutoHotkey script (anticipated some 10 posts ago) turned out to be an excellent solution to that problem and with it I am now able to log in a reliable and detailed way all system power-down/up activities.
I understand that his script might be somewhat elaborated before an eventual release but with dmg's approval, the executable that I am using now (which is my version of his original script) can be downloaded (along with a concise Readme) here:File name: Activity Logger.rar File size: 199.69 KB
Thanks again to all participants to this thread and especially to dmg for his brilliant solution.