I just purchased a domain with hosting a few hours ago. This is my second domain for this account.
The new domain was listed in My Domains list along with hosting. I created files in host but noticed the name servers were created from purchase to point externally. I tried editing to point the name servers to ns21/ns22 but the icon to edit that line was inactive.
So... I exported a dns template from another domain that was working, opened up the new domain and imported template into the newly purchased domain. When I checked the control panel, the domain is gone from My Domains.
Can you import the default settings again and point to godaddy name servers?
For a domain to work it has to be using the specific name servers designated for that particular hosting account. You want to find out what that new account's name servers are -- here's a page on how to do that.
You'll also want to double-check that you have your domain set for your hosting account.