I'm working on a system (p4-1.6Gb NTFS) and after doing a Norton Liveupdate and rebooting, the system came back saying it could not start because PCI.SYS could not be found ot was corrupted.. I tried everything I know (not much ) to "repair" this.. (chkdsk etc. )I even expanded a new pci.sys from the cd, no luck. I tried restoring the registry as well with no luck. Eventually removed the harddrive, and installed it as a secondary on another machine.. saved what files I needed to save, then did a format/reinstall of XP Home. Of course, everything works fine now, till the next time.. but I think MS had better do something to fix this "fatal" error pronto, but I guess it's unlikely as I understand that these types of errors have been around since W2K, especially the "windows\system32\system" corrupted error. This is the second system I have had to do a complete reinstall on, and the people are not too happy.. especially one person I know who lost hundreds of her digital photos by trying to fix it herself.. Has anyone else seen this pci.sys error and recovered from it??