Have you ever wondered why your hard disk LED is constantly on without having any applications reading from the disk (or at least that is what you think).

I was in that situation numerous time, leaving me having to bear with a slow system untill that application decides to stop reading from the disk.

Few days ago I came across these set of tools (originally developed by Synternals) on the microsoft technet website which amongst these list of tools there is an application, ProcessMonitor which actually tells you which application is using your disk, using the registry or network so all you have to do is quit the application/process hogging the disk.

You can download ProcessMonitor from here or the complete suite from here.