I have an XP SP3 system with NAV 2008 that I cannot install NAV 2009 or NIS 2009. I have tried every thing possible short of reinstalling windows (which I will not do). Does not matter if I use retail 2009 cd's or downloaded apps. Basically the install completes but the ui will not open and no icon in system tray. Does not matter if I install over 2008, remove 2008, run nrt, totally remove all traces from files/folders and registry, cold boot install, etc etc etc. NAV 2008 install like a champ. System is clean, no malware, no crashes, no bluescreens, runs great otherwise. uistub generates the dreaded 8504,4 error unable to open this Norton product. I have a few days left on my 2008 subscription and sure would like to get 2009 on it.