Windows 7 lets you search all file types, including unknown ones. Although not recommended because it significantly slows down the search, there may be instances where you need to search unknown file types when you cannot find what you are looking for.

By default, Windows 7 is not set up to search unknown file types. You can configure Windows 7 to do so through Windows Explorer, as described below.

1. Open Windows Explorer.
2. From the Tools menu, click Folder Options.
3. Click the View tab and check “Try to search the content of unknown file types.”

Remember, once you complete your search turn this feature off again so as not to slow down future searches.