If you have the problem that your Magento search does not find any or just a few results, the reason could be that you removed the catalogsearch.leftnav block. This results in wrong search functionality. Do not ask me why! It seems to be a Magento bug since it can be reproduced with standard Magento 1.7.0.2 and sample data. If you search for „sony“, you get three results and after removal of the block you only get one. I submitted a Magento bug report and hope it will be fixed 🙂