I have seen this in an enterprise environment where we use a software distribution system. I suspect a Microsoft patch or update could have overwritten or damaged the file. But like you said this would seem to be a critical system file and without you can not perform any software installations without this particular file. I am also looking forward to seeing an answer for this problem if anyone else has an idea or opinion. -----Original Message----- From: Personal Computer Hardware discussion List [mailto:[log in to unmask]] On Behalf Of Hugh Vandervoort Sent: Tuesday, April 11, 2006 2:40 PM To: [log in to unmask] Subject: [PCBUILD] Autoexec.nt missing I was trying to install AVG on a Dell 4500S today and got a 16 Bit Subsystem error. I was also unable to turn on XP's firewall. I subsequently discovered Autoexec.NT was missing. This is a reasonably well maintained machine with a timid user who only uses it for email. Her 20-something daughter occasionally uses it for email also. I was able to extract the file and solve the problem, but I'm wondering how this important file could have gone missing. The logs show no signs of viruses or Spyware. Any thoughts would be appreciated. PCBUILD's List Owners: Bob Wright<[log in to unmask]> Drew Dunn<[log in to unmask]> Visit our website regularly for FAQs, articles, how-to's, tech tips and much more http://freepctech.com