Note how that FAQ mentions, with emphasis mine:
Microsoft automatically disables Fast User Switching in Windows XP when a GINA.dll is specified in the registry.
Which is why you have came to the suggestion:
This article mentions a registry edit, however they key they mention, GinaDLL, does not exist at the WinLogon registry point.
Luckily you are smart enough to not just simply create that entry, because let's see what Microsoft has to say about GINA, deep in the development center we find:
Note: GINA DLLs are ignored in Windows Vista.
Exactly, GINA is longer supported since Windows Vista. So, not the right way to go about this...
Now, if that software can disable Fast User Switching, we can do the opposite:
Start the Group Policy Editor (Start -> Run ->
gpedit.msc).Go to Computer Configuration -> Administrative Templates -> System -> Logon.
Set “Hide entry points for fast user switching” to “Not Configured” or “Disabled”.
Do a
gpupdate /forceto update the registry, add/bootif you wish to reboot and reload it.
If you don't have the group policy editor, you can:
Launch a registry editor (Start -> Run ->
regedit.exe)Go to
HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\Delete
HideFastUserSwitching.Optionally, reboot your system to reload the settings.