I use spotlight all the time to launch applications and open files. I recently ran into some trouble with files and applications disappearing from the spotlight index. I was able to fix the problem by deleting my spotlight index and rebuilding it.
System Preferences - Spotlight
First you should just make sure your spotlight settings haven’t caused the problem before you take the time to delete and rebuild your spotlight index. In system preferences go to spotlight. There are two tabs: Search Results and Privacy. Make sure the type of file you are looking for is selected and under privacy make sure the file isn’t located in any of the locations specified. Any location specified in the privacy tab will not be indexed.
To delete and rebuild your spotlight index open up your terminal and enter in these commands. (You will need your root password to execute these commands)
NOTE: For most, copying and pasting these commands will work just fine. For some of you it might come back on the first command that the file was not found. If this is the case for you it’s ok, we just need to find the right file. Paste the first line all the way up to the “V” like this: