I have transferred the site's files into the new hosting. If some are missing we will upload them. You must apply and connect the latest database that i will give you.
Site was active under a different URL that domain name does not exist anymore. You must make the installation work fully under the new domain name. Replace all references from old domain name to new one. All urls, pics, media, must resolve, checkout process should work.
Security: Check all Interspire file Permissions. Protect admin area by creating htacess or similar protection.
Clean: Throw out the files that are useless bloat.
I expect you to be an expert regarding interspire cart and know the settings and code professionally and you can finish this job without trail and error.