Like many people using Windows operating systems, I face daily file locks. By searching for applications to solve this issue, I found these:
- Unlocker (freeware), which lists the locks that appear in a file or a folder
- USB Safely Remove, which safely removes a device and, in case the device cannot be removed, it lists the locks

Note: You can get a free one-year license for USB Safely Remove, by visiting this web page, from 27/11/2008 until 5/12/2008.