Question : Problem: Server will not boot after adding /PAE to boot.ini in order to use 16gb ram

I upgraded a server from Windows 2000 Server Standard edition to Windows 2003 Enterprise edition by running the upgrade procedure from CD - (in other words, not a fresh install of 2003). I have 16gb ram which BIOS sees. Windows will only see 4gb of ram. After adding /PAE switch the server will not boot. I can boot in safe mode and remove /PAE and come back up normal. Of course the purpose of all this is for windows to see 16gb ram. Should /PAE work after doing an upgrade or does it have to be a new installation?

Answer : Problem: Server will not boot after adding /PAE to boot.ini in order to use 16gb ram

Problem Solved - I installed Windows 2003 service pack 2 and after it rebooted Windows has 16gb ram. I didn't even have to add the switch.