Program files are a directory of the third-party application software installed on the computer. Both 32-bit and 64-bit software programs can run on 64-bit Windows operating systems.

Normally, if you change a file’s extension in Windows, it doesn’t do anything positive. It just makes the file open in the wrong programs that can’t decode what’s inside.

If you’re looking for a good software to edit large text and various programming files, then PilotEdit Lite is a good bet. It can edit, sort, compare, merge, encrypt and decrypt large files of 10GB.

In the CMD window, type assoc followed by the file extension whose default program you want to determine and hit Enter.For example, to know the default association for .txt files, run: ...