A very handy utility to have when you are troubleshooting is an application called FileMon by SysInternals. This application monitors all (and I mean all) disk I/O on your computer and can help you easily diagnose if a certain process does not have access to a certain file. Once launched your screen will almost immediately be filled with activity, but fear not; there are filtering capabilities so you can quickly find what you are looking for.

Download it here: www.sysinternals.com/Utilities/Filemon.html