Hi, I recently moved one of my sites from asp to php platform. All the urls are different. I asked my host to do a 301 redirect (which I don't know much about), but the redirect is not working, and return 404 error. I now have about 5000 pages in supplemental results. Someone recently told me that if I don't get this addressed, my whole site will disappear from Google. Can anyone shed some light on this? I was also told the only way to rectify this is to do a redirect on every individual page, or a manual removal of old pages.
Yes, you would have to create a htaccess file or do this inside IIS. Since the URLs changed you cannot do a uniform move from x.com/help.aspx to y.com/helping.php for instance.