Problems upgrading from Vista Home Basic to Vista Business

My son has an identical problem. Interesting that Micro$oft choose not to involve themselves with questions of this nature. Too difficult I guess. My son's laptop is a brand new Dell with Vista home and M$ Office. We purchased Vista Business but the upgrade dies with a ""Windows could not prepare the computer to boot into the next phase of installation" error message.I noted there are dozens of similar problems on the web but M$ is strangely quiet about this problem andthere appears to be no solution. Micro$oft are prepared to take the cash for the upgrade but not provide the support...