Well this suggestion sounds daunting but it is really simple and it will make you feel like a pro. So follow these steps:
1. Navigate to /Applications/Utilties/ and launch the application "Terminal".
2. Once Terminal launches and you get a prompt to type: sudo mdutil -E /
3. When it ask for a password put in your Macs password and it will run for about ten minutes( it will be a longer time for the older Macs). Let it run until another prompt comes up in Terminal (don't close Terminal until this happens).
Good Luck.