A checklist for when you change the domain for a Drupal site.
DNS setup to point the domain/subdomain to the right server
VirtualHost entry updated
clear cache (manually in the database if need be)
rename the appropriate Drupal sites directory in the file system
setup symbolic link from the old domain? Only if there are direct links to files, and private files is not enabled
update the files path if necessary admin/settings/file-system
admin/build/modules and save to update module locations
admin/build/themes and save to update theme locations
remove the DNS pointer for the old domain/subdomain, setup a redirect if necessary