Upgrade to Vista Ultimate from Vista Premiun

Hi,
I recently brought a new PC with vista Home premium on it and wanted to
upgrade to Vista ultimate by using the vista ultimate upgrade CD. I did the
update and every thing went fine till the last step in the upgrade
(Completing Upgrade). In the fifth step, the computer did restart and
displayed a message that windows is starting vista for the first time. After
wards, the screen freezes. I had to shutdown the PC after an hour. The good
thing is the old OS is restored.

Has anybody faced this problem?. I would be happy to provide any additional
details needed.

Thanks in advance.