I have the windows vista ultimate product key but don't know how to upgrade ?

Im currently running windows vista home premium and like to upgrade to windows vista ultimate.

I don't have the windows vista anytime upgrade disc but i do have the ultimate key.

how can i upgrade it ?

If you own the windows vista anytime upgrade disc can you tell me its size as well is that 2.52GB ?

Thanks alot .

I have the windows vista ultimate product key but don't know how to upgrade ?computer security

you have to buy it from microsoft web-site, microsoft doesn't care about keys as much anymore cuz this key system failed to prevent piracy. getting a key is not a problem. i suggest downloading an iso and burning it with nero as an actual dvd and then let it upgrade ur vista. i advise using thepratebay.org and the key will also work if it's real, ur system will pass Genuine Validation process after that