Sometimes Windows search engine cannot find a file when it is in the sub-folder or the entered named does not correspond to the real name. The best thing to do is then to use a powerful software like MultiFind Pro to search files.
MultiFind Pro allows you to search files using different types of criteria: text string, regular expression, file size, installation date and much more. It lets you select your own criterion and launch several searches in different tabs. When the search is finished, it displays in the search result all lines which contain your key word so that you take the one you need. MultiFind Pro can be integrated easily into Explorer and supports several file formats: DOC, XLS, PPT, PDF, HTML and RTF.