4
When moving host you are copying a set of files from one host to another, moving the database, and changing mainfile.php to reflect the changes.
Once this is done there are a few things that can still cause problems with the new site, cached folders and absolute URLs.
First as long as the cache, templates_c, and the uploads folder are chmod 777, clear the cache and templates_c folders as they cache files that may point to your old site still. The files will be regenerated automatically as long as those folders can be written to by the server.
Any absolute URLs such as
http://www.yoursite.com/sample.gif that you entered in your site to images or pages will need to be edited manually to the URL of the new site.
HTH.