Index Files Search Words Lite (free) is a program which does the job it's supposed to do--indexing files and letting you search for them--but really seems to be more a "demo" than a "lite".
What it does: It indexes a text or HTML file (or a "text-like" file, any file which only contains ASCII characters between 32 and 255, and the whitespace characters--a typical example is a source code file for C++). Once it has produced the index, you can search for a word, a phrase, or a set of words within the file, and a report showing the words and a small bit of context will be generated. Index Files Search Words Lite is straightforward,--though the interface is a bit on the clunky, ugly, and dated side--and the response time is quite good. The reports it produces are functional and useful.
What the problem is: Generally, if you want to find a word or phrase in a single text file, you can do this pretty easily with a text editor. While the context provided by the report is nice, it's not vital when dealing with a single file. The kind of functionality offered by Index Files Search Words Lite is most useful when dealing with a lot of files--a folder full of legal documents, for example, where you may wish to find every reference to a particular name or case. This kind of functionality is the province of the "non-lite" version. While I can see some edge cases, especially with very large files, where Index Files Search Words Lite would be useful, they're not all that common.
Further, Index Files Search Words Lite cannot search in Word documents or PDFs, two of the most common formats--it's limited to basically plain-text files, as noted above. This further undermines its potential utility, though it could be helpful for documenting function and variable names in source code, provided the source code was in a single, large, file.
Though Index Files Search Words Lite not positioned as a demo or trial, in this reviewer's opinion, it is, and it should be downloaded and evaluated as such.