User Logger

From the developer: Logs computer usage information about who used the computer it is installed on, and when. Optionally include all sorts of other useful information, such as what programs were being used and computer ID info. Optional Screen Captures at intervals. It runs invisibly and can be disguised in the Windows Task list. The log is a tab delimited text file which you can drag-and-drop or import into any spreadsheet and analyse.

Limitations:

Encryption, scheduling, key capture are disabled.