A cool little known feature of Windows Notepad is that it can be used as a log with the time and date of entries. When Notepad is opened, the time and date will be placed at the end of the file. Then you can add information at the bottom of the file. This can be a useful thing when recording items over a span of time, such as a changelog in a server environment.
To do this, simply put .LOG at the top of the text file in Notepad. Note that the word "LOG" has to be in all caps. Then, save and close the file. When it’s opened again, then Notepad will automatically add the date and time at the end of the file. You can then start typing any entries.
What’s also very nice is if you need to add the date/time to a file when it’s open, simply hit the F5 key. This will put the date and time at the current cursor position.
Microsoft has a KB article here: http://support.microsoft.com/kb/260563