It seems that the sfi.dat file is still preventing system restore from working. I had a problem yesterday where my optical drive just suddenly disappeared from both My Computer and Device Manager and was not being detected by Windows at all. One of the “solutions” I found was to restore the system to a previous date. None of my restore points would work, they kept saying that Windows could not be restored and no changes would be made. I remember that it was confirmed a while back that sfi.dat was the cause because it’s a locked file that can not be accessed or changed except by CIS. Isn’t there a way this can be fixed?
I did get my drive back using a script from the excellent site for XP at http://www.kellys-korner-xp.com/xp_tweaks.htm