Can I use Windows 7 Ultimate Upgrade version DVDs to upgrade my Windows XP Professional x64 computers?WindowsMarketplace.com says:Microsoft designed Windows 7 Upgrade media for Windows Vista. Customers with Windows XP can purchase Windows 7 Upgrade versions but must back up their files, clean install, and then reinstall their applications. So if I have to back upmy files, clean install, and then reinstallmy applications, then what's different from a full install?And what are the differences between Windows 7 Ultimate Upgrade versions and Windows 7Ultimate Full versions then?

Hi, To use the Upgrade Version, you must have a XPor Vista installed on the computer.In the case of XP you would be asked to do a clean install. Because it can not be upgraded to W7 .Go to this link for a way of upgrading XP http://technet.microsoft.com/en-gb/windows/dd671583.aspx?ITPID=tnflash You would have to use the Full version if did not have a XP or Vista installed. Vista can be upgraded, as long as it has SP2 and is the same (ie Vista32bittoW732bit. or Vista 64bit to W7 64bit. ) Slan go foill, PaulAlso go to this link for more information. https://ozndfq.bay.livefilestore.com/y1m5OMQdgsShJH1LoXA5f1pBn436a4VRX5BnMBGdDbh7gNV6m8uIgv4kCW5CfgNDwtEYgFFiO60_WVMD8q5XfMQgdHUtBUszHVhlEFLa0W0haBV4CfxotFYs1C5A-CzQmr_FKt1_QtMVKVnSeHZNKsPKw/windows7-upgrade-chart_thumb[8].png

almost correct It is however not necessary to actually have the previous OS installed when using the upgrade version. You will just be prompted to insert a CD/DVD with the qualifying product during setup.

almost correct It is however not necessary to actually have the previous OS installed when using the upgrade version. You will just be prompted to insert a CD/DVD with the qualifying product during setup. Has anyoneactually verified this with a Windows 7 Upgrade DVD or image?If not, this is purely conjecture.On another note, I booted the Windows 7 Enterprise Evaluation DVD on a computer that had only XP Pro. x64 on it, and it offered to upgrade. I didn't attempt it, preferring to do a fresh install on a new hard disk. But I wonder what would have happened if I had. Also, it might have something to do with the fact that I once had Vista installed with the XP, in a dual boot configuration. The boot partition still has a bootmgr boot sector and BCD on it.

almost correct It is however not necessary to actually have the previous OS installed when using the upgrade version. You will just be prompted to insert a CD/DVD with the qualifying product during setup. Has anyoneactually verified this with a Windows 7 Upgrade DVD or image?If not, this is purely conjecture.On another note, I booted the Windows 7 Enterprise Evaluation DVD on a computer that had only XP Pro. x64 on it, and it offered to upgrade. I didn't attempt it, preferring to do a fresh install on a new hard disk. But I wonder what would have happened if I had. Also, it might have something to do with the fact that I once had Vista installed with the XP, in a dual boot configuration. The boot partition still has a bootmgr boot sector and BCD on it. With respect to your question, my understanding is that it is at best conjecture - actually, the last I heard it is in fact not true. So far everything in writing indicates that the old OS must be installed and activated.The other issue seems to be a bug in the installer. I got the same option doing a clean install upgrade of an older XP laptop, and when switching the same laptop from the 64 bit to 32 bit version of the RTM. Since going from XP to Windows 7 or 64 bit to 32 bit (or vice versa) absolutely should not work asinplace upgrade paths, they really should clean that up. If the option doesn't work, it really should not be present....Stephen