Heres what I did, last year after sp1 was released I ordered a Home Prem x64 vista upgrade however I didnt get a sp1 version (it was only like 3 weeks after sp1 was release to the public). Anyways Ive had to do the remove ram thing where its down to 2gigs since my bios wont allow me to turn off ram. So Anyways I dont want to have to go through having to remove ram to reinstall vista again if such comes into play. I have thought about going to Acronis but to be honest Id just rather make a sp1 disk like we used to with xp and others. So anyways heres what I got and have done. 1. I copied my vista home prem ENTIRE disk to desktop, 2. I then also put the x64 sp1 on desktop and ran vlite, 3. I chose my version of vista (home premium) 4. then I choose service pack slipstream and bootable ISO 5. Walked away for a couple hours and came back and it said it was finished. 6. Then I told it to create a ISO 7. It told me my size was bigger then 4gigs 8. So I went back and told it to "rebuild one" 9. It finished and I again said create a ISO 10. It went without a issue 11. After it was all done I told it to burn image and after done it said write sucessful. So now Im guessing I have a bootable sp1 home prem vista x64. So how does this work with upgrading and installing. I know my retail disk has both full and upgrade versions on it. So which (full and upgrade) did the Vlite build, or did it build both. So can I do a full install and upgrade install with this disk and it will be a sp1 version. Ive noticed in vista to do the upgrade ive had to be in the previous OS to do the upgrade. Im saying all this to avoid having to remove ram.