Google search revolutionized the internet. Desktop search is the same idea applied to the files on your computer. A background service monitors for file changes and indexes file content and attributes in a system database. You can then query the database for keywords and get to the file you need quickly. xplorer² old style search on the other hand doesn't use an index, it scans your folders every time you do a new search — that's why it is slower (and more robust).
The good thing about windows search is that you already have it installed and running (if you are on windows XP or older you can download it). You don't need to install extra programs. The search results are presented in a window like normal files (not like unusable text as in google desktop search). You can specify a search location (starting folder) to narrow down the results or you can search your whole hard disk if you can't remember where your files are at all. Resource-wise, if you have a modern computer you won't notice any delays from running the background indexing service. The index file itself WINDOWS.EDB is 750MB on my system — hardly noticeable in a 500GB hard disk.
The default search settings are reasonable for the average user. The index includes emails and files under My Documents (C:\USERS) where most of your files are. If you have text files and documents in other locations just find the Indexing Options applet in the Control Panel, and add extra folders e.g. the PSDK include folders.
Windows search will index file properties (filename, size, date, author etc) as well as file content. When you search with google, you don't specify the date of an internet page, but in windows search you can. In fact the query language is fully featured SQL which means it supports complex boolean searches on attributes and content.
The fundamental problem with index-based search is that it only finds whole keywords. You can't search for something in the middle of a word. Also you cannot search for any special characters like brackets or punctuation marks. However most of the time you don't need anything but a whole name, so this limitation isn't an issue.
Another big limitation is that the index only works with local files and folders on fixed disks. It won't find files in removable devices like DVDs or USB disks, and neither will it work for network folders. If you cannot find files in your local hard disk, make sure the container folder is included in the indexing options (see pic above). Also note some folders are excluded, a concept similar to xplorer² black list.
The forthcoming xplorer² ultimate will automatically use desktop search as a first attempt, and if it fails to find what you are looking for, it will fall back to the traditional robust search you are familiar with. This way you get the best of both worlds, the opportunity of a fast match (WDS), and the trustworthiness of choo-choo search. I have translated most of the xplorer² search options in a WDS query so the search GUI didn't have to change. Only a few complex searches cannot be routed through WDS:
If you want to test this exciting new functionality just get the latest ultimate version beta.