The re-index option should only be used if you encounter a
database error or are directed by support to correct the error.
1) Click on Utilities: Re-index.
2) The Re-index Wizard will open, click
Next to start the index process. 
3) Choose a farm to index by clicking in the check
box, then click Next. 
4) Click OK and then close the re-index
wizard window by clicking Done. 