You might have to enable 'searching within files' on the folders you keep your workbooks in, also indexing those locations will make the searching faster.
Click on : start (which is left side bottom button)
Click on : search
Select "All Files & Folders
in A word or phrase in the file: type which you want i.e. Tubelights
In Look in option : You can select drives or if you know folder name then click on browse & select your specific folder.
I hope your problem is solve.