I run Vista Home Premium on my Dell XPS M1330 (Alienware) laptop. Since my previous install ran into trouble, I completely formatted and re-installed the laptop. History: I used to run this Vista version, then did an upgrade to Windows 7 Home. Aside from some driver problems, this ran perfectly. Then the W7 stopped booting. I formatted the drive, installed Vista from the laptop recovery disk and ran all possible Windows updates. I did not install any other software. During those updates, after rebooting, the system would occasionally just turn off before getting to the Vista login screen. Starting the system again, it would work fine. Now I have W7 Ultimate (student license) and want to do an upgrade from Vista. Last time this worked fine, and it seems to work fine now as well. But if the system reboots for the last part of the installation (loading W7 to complete the install), it turns off in the process (21% of unpacking files). Next time I boot the system it restores the Vista install and I am back at square one. Is this a hardware or software problem? Does anyone recognize the symptoms? I'd really like to start using W7 again. Thanks for reading!