let Windows display all file extensions so you can see exactly
what you're dealing with.
First, double-click on My Computer. In the resulting window,
select Folder Options from the View menu. In the Folder
Options window, click on the View tab. On that tab, you'll see
a scrollable list of items under the heading of Advanced
Settings. Look for the option that says, "Hide file extensions
for known file types;" there'll be a checked box next to it.
Click on the box to uncheck it, select OK on your way out, and
you'll be set. Now you won't be fooled by bogus file names.