IsSearch - description from Softdepia.com:
This program is based on Windows Indexing Service allows to carry out instant search on huge number files of the following types:
txt - plain text files;
htm, html - Hypertext Markup Language texts;
doc - Microsoft Word documents;
xls - Microsoft Excel documents;
ppt - Microsoft Power Point presentations.
Also you can search any other document for which a document filter is available.
You can execute simple or complex search according to your needs (using boolean operators And/Or/Not/Near or without them). Results of search are sorted by rank. Each found file you can look with internal browser or an associated browser.
The search is executed very quickly, as it is carried out by means of preliminary indexing of files. The indexes are built and supported automatically by Windows Indexing Service, you only have to specify the location of files in which the search is to be executed.
IsSearch is a "Free to try" program. You can download and try it for an evaluation period.