MythicSoft's FileLocator Pro ($40) offers extensive search tools for those who need to dig among a variety of file types and content to find one specific piece of data. The free version, Agent Ransack, would likely suffice for all but the most demanding data sleuths: This paid version is for the pros.
Available in 32-bit and 64-bit versions, FileLocator Pro's basic user interface allows for using Boolean searches, DOS expressions, regular expressions or exact word matches to find particular file names and content within those files. You're likely familiar with DOS expressions, which use '*' as a wildcard, for example, as well as the "and, or, not" qualifiers for Boolean searches. On the other hand, regular expressions allow for more specific searches, but are correspondingly more difficult to construct. Matching file name results display in the lower left, with details such as location, size and file creation time. Clicking one of those filenames displays matching content within that file on the right side without having open it. Clicking a '+' next to matching content displays the lines surrounding the match, a nice feature. And double-clicking a file name opens it using the default program.
While the basic interface allows for in-depth searches, FileLocator Pro's real strength lies in its expert user options, accessible by simply clicking the "Expert User" box in the upper-right. Doing so opens up five additional tabs of search options, such as selecting date ranges for modified, created and last accessed dates; checking files with the hidden, read-only, system or other particular attributes; or searching within a variety of compressed and archived file formats, including .zip, .rar and .iso.
For example, one expert search might entail sifting for documents currently within a .zip file that were modified between 7/1/2009 and 12/32/2009, have "Larkin" in the file name and the word "security" within the document. You could also use much more extensive search terms with Boolean operators or regular expressions.
FileLocator Pro has a well-laid out help file, as well as a wizard that can help construct your search terms. In the expert mode the wizard recognizes your current choice of search type, which can be of particular help when constructing an arcane regular expression, normally the province of programmers. This file management utility also allows for saving your carefully constructed searches for later use, or exporting search results to a variety of formats, including tab separated, XML or HTML.
If you need full-featured searches and you're willing to pay for them, FileLocator Pro could prove an effective spotlight. The company also offers a stripped-down free version called Agent Ransack that lacks some Pro version features such as searching within archive files, but can still do much more than Windows Search.