KeyCounter is a tiny program which tracks PC activity by recording when a key is pressed, or the mouse is moved.
Note that the program only records when these things happen, not the specific details. So you can use it to see that, say, a lot of typing went on between 9 and 10am this morning, but it won't tell you exactly what that typing was.
Still, this can still be very useful if, say, you need to complete a timesheet to record when you were working. Or if you think someone else is using your PC when you're not around and you'd like to collect more information.
Whatever your purpose for running the program, it's very easy to use. Just run the small executable and it begins collecting keypress and mouse movement data. And, later on, when you want to review your activity, just right-click the KeyCounter system tray icon and select Today to see what's happened in the past few hours, or History if you've run the program before and want to view previous days.
KeyCounter is very basic, then. But it's also very small, consuming under 2MB of RAM on our test PC, and if you only need to maintain a simple activity history for your system then the program could be ideal.