Windows Search for unknown file

Recently I was trying to search through a group of files for a particular word. Usually there will be a box to type in the text you are looking for, and windows scans the text of each file to find your word. But this time it was not working. The reason is that I was scanning a bunch of PHP files for a particular piece of code. And even though I knew that code existed in these files, the Search Assistant was saying "There were no results to display".

At last I found the solution:

Step1: Click Start, and point to Search, and then click For Files or Folders.
Step2: Click Change preferences, and then click With Indexing Service(for faster local searches).
Step3: Click Change Indexing Service Settings (Advanced).
Step4: Click Action from the menu bar and click Properties.
Step5: On the Generation tab, click the check box to select the Index files with unknown extensions check box, and then click Apply and OK.
Step6: Close the Indexing Service console.

Note: If you have opened any search window please close it after the above setting and reopen it again for your search.