I'm not sure sure what you are asking for advice on. Is it to find the files you have already created or just to open the one you think is a Gedcom file? It would help to know if you created the files in the first place, and if so how? For instance if you have some FH software on your computer/laptop etc that this is also the best way to open the mystery file. It is also the best tool to create new Gedcom files assuming that you have the original tree information in the program. If you obtained the Gedcom files from someone/somewhere else then ideally you need to use some specific FH software to open and display the contents.
PhpGedView is quite good for that. Gedcom files are basically text files so you can 'open' them using any text based program such as Notepad, Word etc, although obviously that won't display the data as a tree, but it will allow you to scan through the file looking for obvious corruptions, which you may be able to correct manually if you know how the structure works. The Wikipedia article on Gedcom files is good place to gain a basic understanding.
Apologies if I have misunderstood your problem.
