This is one of a large number of excellent free tools available from SysInternals.
Process Monitor is an advanced monitoring tool for Windows that shows real-time file system, Registry and process/thread activity. It includes rich and non-destructive filtering, comprehensive event properties such session IDs and user names, reliable process information, full thread stacks with integrated symbol support for each operation, simultaneous logging to a file, and much more. Its uniquely powerful features will make Process Monitor a core utility in your system troubleshooting.
Here is an example of what it might look like:
You will want to set up filtering or you will be swamped with way too much data.
|File Monitoring Alternative - ProcessActivityView|
If you only care about file activity (what files are accessed and how often etc) by a specific process you might find that the NirSoft Process Activity View is an easier way as it summaries file activity.
From the web site: ProcessActivityView creates a summary of all files and folders that the selected process tries to access. For each file that the process access, the following information is displayed: Number of times that the file was opened and closed, number of read/write calls, total number of read/write bytes, the dll that made the last open-file call, and more...