Index Your Files is a free software for both Macs and PCs. You simply choose which files you wish to index, configure how it is sorted, downloaded and installed. Windows automatically indexes all the files on your computer, including its own files, folders and drives, to speed up searches. To really take advantage of indexing on your files, you need a good dedicated search and indexing tool, ideally one that is also fast. There are a few tools that are very good, but not all of them are equally effective or even good.
IYF is one such excellent utility, which indexes your entire Windows database - even your hidden ones! The best part is that you can use it to run multiple scans on your entire hard drive (that includes your recycle bin, temporary Internet files etc), thus making it useful for cleaning up the registry as well. You can also specify what to do with each folder individually, making it especially useful if you use many folders. You may for instance remove all the duplicate files in all the other empty folders, or only index those files you really need.
IYF also comes with an automated scheduler that lets you schedule when to perform backups or complete other actions. It also lets you schedule regular scans to make sure you don't miss any indexing drives or important files. And it has a simple user interface, letting you just select a folder or set the parameters for searching and indexing.