i have an intel 20" iMac. ih ave boot camp and was running a beta version of vista ultimate on it i received from microsoft. it expired last week and will now only let me open it in safe mode and use IE explorer. i then purchased vista ultimate upgrade from windows marketplace and stored in my digital locker. i tried to download it but it keeps giving error messages like my serial number is not valid etc. actually it is asking for some other type of number that you can only get if you have a disc or if the download was successful which is ludicrous if you can't download it and install it to begin with. i have gone round and round with this marketplace support and windows vista support and it getsm e nowhere. im going to try and get my money back for the download and just go to a store to buy a disc now. so my real question is this. if i am going from an expired version of vista ultimate beta, can i buy the ultimate upgrade or do i have to purchase the whole operating system?