Magento Search Doesn’t Work Properly

Yesterday i worked on magento searching result page, everything almost been done. But when i typed some words and tried to searh some products in demo sotre, 50 products at least came out on the page, but there was none related with the keywords i typed in the search blank, that’s really weird!
Re-indexed all data and clear cache, but nothing changed!
I checked all relevant template files, finally found that, i comment folling lines in catalogsearch.xml
path: app\design\frontend\your_template\your_theme\layout\

<reference name="left">
   <block type="catalogsearch/layer" name="catalogsearch.leftnav" after="currency" template="catalog/layer/view.phtml"/>

Just un-comment or add these lines in catalogsearch.xml, everthing goes right again!