Put .LOG at the beginning of a text file. When opened in Notepad, you should get a date & time stamp.
Open filename.txt, type something, save and close.
Now you have a journal for system and config changes, document collections, time entries, client visits, whatever. Has worked on every Windows box I ever had to use.
Find your half life by eating this? Even though only 2.4% of the "original flavour" remains, consuming that tube will shorten your life as well.