Check the existence and value of this registry key:

HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\TSAppCompat
0 is Remote Administration, 1 is Application Server mode

Note that this key will let you see what mode the server is in.  
You can not switch between the modes just by toggling the key.

--
Vera Noest
MCSE,CCEA, Microsoft MVP - Terminal Server
http://hem.fyristorg.com/vera/IT
*----------- Please reply in newsgroup -------------*

"David De Bono" <er_fortsatt@hotmail.com> wrote on 13 jun 2005:

Call IsOS(OS_WIN2000TERMINAL).

Review IsOS for other values you can query that may more precisely cover the
specific terminal services case you're interested in, but which you didn't
detail in your question.

You can also call GetVersionEx and check the value returned in wSuiteMask
for VER_SUITE_TERMINAL and/or VER_SUITE_SINGLEUSERTS.

If you're only testing, using VerifyVersionInfo with arg2 = VER_SUITENAME
can make your life easier.

Here's a simple way if you are checking from the user's standpoint:

Bases on SESSIONNAME env variable. You might need to test to make sure it is
not XP and is truly a server first so you dont get a false positive from
XP's remote desktop feature.

if environ$("SESSIONNAME")="CONSOLE"
   Terminal services enabled, but is running via console
if environ$("SESSIONNAME")="RDP#"
   Terminal services enabled, and running in a RDP session
if environ$("SESSIONNAME")=""
   No term services enabled

-Harry Bates