Before I describe the problem, I should say that I successfully did a clean install of Windows 7 public beta on a new HDD on my PC. However, on the very same PC, I then decided to upgrade my existing Vista SP1 which is on another HDD. So while in Vista, I ran the very same install DVD that I used to do the clean install. Setup started up fine, got the online updates, and did the compatibility checking. Then it started the "upgrading windows" screen where it says "copying windows files (0%)". Within a few seconds of that process starting (still at 0%), up pops a small window that says "Windows installation and Setup has stopped working". The only option is to then hit the "Close" button within that window, and then the "upgrading windows" screen automatically closes and you are returned to the initial install menu. I have disabled my ZoneAlarm AV, spyware, firewall, and program control functions, so that's not interfering. I have retried 5 times to no avail, same result every time. Any ideas what may be causing this?