Enable Multiple Remote Desktop Session on Windows XP

Feb 25, 2011:
How to Enable Concurrent Sessions in Windows 7 Service Pack 1 RTM
===

1) Obtain patched termsrv.dll that matched your current version

2) Backup original files in the following folder:
system32
system32\dllcache
ServicePackFiles\i386 (if exist)

3) Create registry file (for example, we'll name it ts_multi.reg)
[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Terminal Server\Licensing Core]
"EnableConcurrentSessions"=dword:00000001

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
"EnableConcurrentSessions"=dword:00000001

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
"AllowMultipleTSSessions"=dword:00000001

4) Create Scheduled Task (run with administrator level privelege)
c:\windows\regedit.exe /s c:\windows\ts_multi.reg

5) Use gpedit.msc to edit this policy:
Computer Configuration -> Administrative Templates -> Windows Components -> Terminal Services -> Enable Limit Number of Connections

In the case that remote session is only possible if a user with administrator level logged on first then you must add the ordinary user that usually log on to that machine to local Administrators group.

Source:
Enable Multiple Concurrent Remote Desktop Connections
or Sessions in Windows XP
www.mydigitallife.info/2008/06/13/enable-multiple-concurrent-
remote-desktop-connections-or-sessions-in-windows-xp/

Dont forget to read Comments as well
especially by sweetsinse on September 16th, 2008 22:20

"Backup" article (with "backup" download links):
Ativando Multiplas Conexões Remote Desktop no Windows XP
http://sobrepcs.blogspot.com/2008/11/ativando-multiplas-conexes-remote.html

Easier way that works for me (only tested with XP SP2)
Multiple Remote Desktop on Microsoft Windows XP, Vista and 7
www.linuk.web.id/2011/04/multiple-remote-desktop-on-microsoft.html
Caution:
When run, Universal Termsrv.dll Patch try to connect to Internet, so it's better to disconnect your Internet first or use firewall to block it

Related article:
Windows XP SP2 tcpip.sys connection limit patch
www.speedguide.net/articles/windows-xp-sp2-tcpipsys-connection-limit-patch-1497

Free Multiple Remote Desktop Sessions in Windows
http://lancore.sourceforge.net/en/multiple_remote_desktop_sessions.html

Alternative (paid) solutions:
Concurrent Terminal Services (RDP) sessions under Windows XP!
http://tinyapps.org/blog/windows/200708080715_windows_xp_terminal_services.html