If you're looking for a particular file with a known filename, I cannot recommend enough voidtools.com Everything search tool. I seriously don't know how I got along without it. It indexes every file on fixed disk locations (takes a minute or so on first startup) and after that, it winnows through the file list as fast as you can type. Works with wildcards as well. I have mine running on startup and bound to Win+A.
It's really great for finding duplicate files, projects, different DLL versions.
It doesn't look inside the file at all, but for many, many needs I haven't found anything else that can touch it.