File Viewer Lite

File Viewer Lite is a free Windows utility that allows you to view over 150 popular files. It can open Microsoft Word documents, Microsoft Excel spreadsheets, PDFs, audio files, video files, image files, camera raw images, and more. The unique Info panel displays useful information about the file along with metadata stored in the file, such as EXIF metadata for images and audio and video codecs for multimedia files.

While File Viewer supports most common file formats (and many uncommon ones as well), it also displays unsupported file types in both text and hex views. Therefore, you can also use File Viewer Lite to display the contents of unknown files.