Worst case, download FileMon: http://technet.microsoft.com/en-us/sysinternals/bb896642.aspx

It will log every file access on your system. You can set a filter like ("Poser") to reduce the volume of results. If Poser if opening, closing, reading or writing to a file, FileMon will show it. 

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken