One of the many ways to open an archive is by using the drag and drop interface:

1. Navigate to the archive using My Computer or Windows Explorer.
2. Click on the archive and, while holding down the left mouse button, drag the mouse pointer over an empty PowerArchiver window (if you already have opened an archive in the PowerArchiver, it will not open the file, but instead add that file to the currently open archive).
3. Release the left mouse button to open the selected archive.