If your Spotlight does not search for some files or applications:

The first of all - restart the Spotlight:

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist

If it have no effect - remove Spotlight's index:

Stop Spotlight service:

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist

Remove Spotlight index folder:

sudo rm -rf /.Spotlight-V100

Run service:

sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist

After reindex - everything should work well.