First, how are you installing Vista...did you burn a DVD or did you mount the ISO? Burning a DVD tends to be more problematic, and while reducing the speed of the burn seems to help it's still better to mount the ISO using something along the lines of Daemon Tools, which is free.
Second, note that upgrade installations can be tricky. For best results disable any unnecessary software when you launch the installer (if mounting the ISO) and disconnect any peripherals (either way).
Finally, note that Vista is still a bit buggy and not fully supported, so you may not want to overwrite XP at this time. Instead I'd suggest either dual-booting or loading Vista in a virtual machine. (Basically running Vista inside a window on top of XP.) The best free tool for this is VMWare Server, which shouldn't have a problem at all considering you have 2GB of RAM at your disposal.
Hope this helps,
I am using XP and want to do an upgrade install from within the OS. I ran the setup and after a few moments got this message..."Windows Setup experienced an unexpected error. To install Windows restart the installation. Error code 0x0."
I have a Prescott CPU 3.2ghz and 2 gb RAM. I do NOT have Vista Beta, just RC1.
Any ideas on what to do?