PC Usage Viewer is a tiny little freeware that does nothing but shows the times your computer has been active in the past days, weeks, or even months. It collects and analyses the info tracked by Windows (login and log off times) and put them in a visual format that is more understandable. Because of these, you don’t need to put the tool in background collecting the data before becoming any useful.
The tool offers 3 view mode to choose from, Grid view by default, Graph view, and Text view. You can see in details how many hours your PC has been busy each day from each view.
Because it collects the data from Windows log files, you can track as far back as your log file states. You can even go all the way back to the day 1 when the computer was first built, as long as the log files have never been purged.
The only thing I don’t like is that it doesn’t have a portable version for me to put on my USB toolbox. Otherwise, I could use it more often.
PC Usage Viewer works fine on most of the Windows system, from XP to Windows 8, both 32bit and 64bit editions are supported.