Can't launch Norton 360 v3 on XP-pro

Hi there, think something got into the machine, can't launch Norton 360 v3 on XP-pro.  It sometimes doesn't respond, and some others getting plain BSOD.  Other times, it launches but finds nothing in full scans.  Machine seems little slower than before.
What I did was disconnect it from internet, then get an updated (latest - dec/27th) recovery disk in another machine, burnt it and boot from it, but finds nothing in full scan.  Tried several times on different days.
Then, as advised in "How to troubleshoot a suspected Malware infection" (http://community.norton.com/norton/board/message?board.id=Announcements&thread.id=15), checked
- C:\Documents and Settings\ ... \Programs\Startup directories, found nothing
- common loading points using the msconfig utility,
  there's one suspicious unidentified startup item with no command associated, at location:
  HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- registry load points,
  found ctfmon.exe, not sure what is in
  HKEY_CURRENT_USER\Software\Microsoft\Windows\currentversion\Run
  ctfmon.exe DNA REG_SZ C:\WINDOWS\system32\ctfmon.exe
- nothing suspicious in the task manager

Please help.  Thanks in advance.


Regards,


Grd_Nrt