ASP.NET Locks File for a certain amount of time?

[Dave]

I have a static Crystal reports .rpt file that I access via the Report
Viewer in ASP.NET. When I access it on the webpage, even after I exit
the browser and stop viewing the .rpt file, it will not let me rename,
overwrite, move, etc. this file. It gives the message "... It is
being used by another person or program. Close any programs that might
be using this file and try again". It seems that maybe one of the
ASP.NET processes still has a lock on this file. I tried restarting
IIS and that did not resolve the issue. I think after a certain
number of hours it seems to be freed up again. Any ideas?

Thanks!
Dave