The Google Desktop Search software became officially defunct toward the end of 2011. But one can still download the last 5.9.1 version, and it happily installs and indexes and searches the full-text of your content. For instance, a folder full of Gbs of PDF encyclopaedias and journal articles, ebooks, etc, presenting results in a familiar Google Search interface. Note the indexing has to be manually started by you, and this is done by right-clicking the taskbar icon and selecting “reindex”…
But if you need a personal desktop search product that’s being supported and developed, perhaps due to the need to index a new file-format, then the alternatives are…
* the free ad-supported Copernic Desktop Search (or the simplified and apparently ad-free version called Orange Desktop Search). Well-reviewed and mature software. Can be aggressive in its initial indexing, hogging system resources even when supposedly idling and in Restricted mode. There is also a Copernic Desktop Search Professional Edition.
* the free X1 Search beta. Once out of beta it seems this will become commercial software — joining their existing and mature X1 Desktop Search Professional (£37, PC Advisor review from 2011). The X1 website’s main landing page gives the unfortunate impression that X1 is only useful for searching Twitter and Facebook activity (blurgh), but it also functions as a powerful full-text desktop search tool and it seems well-reviewed.
* DocFetcher 1.1 is a Java-based desktop search software, that’s open source and free. It’s been around since 2009, but doesn’t seem to have any genuine reviews (that I could find). Supports indexing of Open Office file types.
* dtSearch Desktop (£119, PC World review from 2011). Another very mature and powerful software, although the price of $199 will likely make it unappealing to personal users. The dauntingly powerful interface will also likely make it unappealing to small business users.
* the free built-in Windows 7 search. Although now tamed, and no longer the terrible disk-grinding Windows Vista incarnation, in my view turning on Windows Search still makes a desktop PC too slow. Especially if you run a PC stuffed to the top with legacy files and emails.