I have XP Pro, McAfee Internet Suite 2007 (installed and Uninstalled) on a 939 system (4200+ 64 processor) - 2Gb Ram 2x SATA drives - Raid 0, X800XT AGP ... I am unable to upgrade the system hangs while gathering information and the Task Manager shows the processor runnimng at 100%. I waited 3 hours and the progress bar was stuck at the same point
if you do a clean install it keeps all the old files from the old stuff in a folder called "windows.old" keep the pics and the documents, with vista. just move them to the documents folder. althought you do have to install all software again
i did an upgrade ,didnt back up anything ,it worked a treat !!!!my pc runs as smooth if not smoother than xp ,(it is only 5 months old )i did abit of research and found that people were getting better results with upgrades than clean install (crazy i know) apparantly a vista upgrade removes all traces of your old operating system,unlike old upgrades ,which installed on top of the previous system,all i can say is it worked well for me !