Most of the times our system is idle and does nothing, so if you wish to find out when your hard disk is processing and when not, then here is a Hard Disk Indicator for your system.
Usually all the CPUs come with a Hard Disk indicator LED light but that is placed on the CPU box and not all people can see it, so here is a tool that can place an indicator right on your system tray so that you can know whenever your Hard Disk is processing and when not.
The tool is called Hard Disk Indicator Pro and displays a red light at the system tray whenever your hard disk is in working state. This will enable you to make out the times when your system is idle and when in use. The colors are also customizable.
The tool is free but the only limitation of this tool is that it does not work on Windows 7.