Windows 7: Excel 2003 file disappears in Windows 7

There is only one of my Excel 2003 files that almost disappears when I copy it over into my Windows 7 laptop and try to read it with either explorer or search for it, although it asks me to replace it everytime. It appears as if it doesn't exist. However when I open Excel 2010 and list only the .xls files, it finds it and I can read it. I have several other Excel 2003 files that are fine and since I usually open files by clicking on them in explorer, this one is particularly annoying, since I can't find it to click on it to open it. When I do open it in Excel 2010 it works normally and fine.

Can anyone tell me why only this file disappears from explorer and the search function only?

Can you copy the data in it to another file and resave it with the xlsx extension?? I would be spooked that it was corrupt in some way if you don't see that same behavior with other xls files.

I don't know, but I have a heck of a lot of sheets and data in it, but it's worth a try in case something's corrupt. But what I can do is to save it as an Excel 2010 file and then I can see it in explorer, search and find it, etc. The problem with that is when I go and try to read it back using Excel 2003 though. Maybe I can try a different extension and see if that works? I'll try your advice and see what happens. Thanks.