- Check your httpd.conf file for mod_rewrite extension. It should be uncommented.
- Check Override permission in http.conf file for .htaccess, If it is "None" make it "All".
- Always restart your webserver after every change made to httpd.conf file.
- Do check your .htaccess name. It should be .htaccess only.
- Do check the code of .htaccess. It should be correct, Otherwise your application will not run.
- If you are using wamp you can enable mod_rewrite module using GUI also.