To enable PAE in Windows Server 2003 and Windows 2000 (and Windows XP), append the /PAE switch to the end of the line of operating system in the Boot.ini file. To disable PAE, use the /NOPAE switch. The Boot.ini normally located in the root folder (i.e. C:\) with Read-Only and Hidden attributes, which are required to be removed before the file can be edited.

For example,

Original Boot.ini:

[boot loader]
timeout=0
default=multi(0)disk(0)rdisk(0)partition(1)\WINNT
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINNT=”Microsoft Windows 2000 Advanced Server”
/fastdetect

Change the Boot.ini to become:

[boot loader]
timeout=0
default=multi(0)disk(0)rdisk(0)partition(1)\WINNT
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINNT=”Microsoft Windows 2000 Advanced Server”
/fastdetect /PAE

For Bootcfg command, use:

bootcfg /raw "/pae" /A /ID 1

Restart the computer after modification to make the change effective.

Note that even with PAE enabled, there is still memory limit imposed by the operating system itself. The table below list the maximum memory support with PAE enabled for Windows 2000, Windows Server 2003 and Windows XP. Most 32-bit client based Windows operating system, such as Windows XP and Windows Vista (see way to use large memory of more than 4GB in 32-bit Windows Vista), has OS level limit that restricts the maximum amount of memory able to be used to 4GB.