Windows Vista Stacking

I have a folder with 28 files in it. 26 are exe (application files), 1 zip
and 1 ram file. In Windows Explorer, when I click on Type, Explorer shows me
I have 3 types of files: application, zip and ram. When I stack by type,
Explorer creates 2 virtual folders: one labeled application and one labeled
compressed (zip) folder. The application folder contains 4 exe files and the
zip folder contains the 1 zip file. Where are the other 22 exe files and why
didn't Explorer create a virtual folder for the ram file?

Thanks in advance.

Dave