In Reader to Reader: "Change the Windows Logon Screen" (December 2002, http://www
.winnetmag.com, InstantDoc ID 26848), Amnon Fiener explains how he was able to change Windows 2000 Professional's logon screen to show a customized logo. He mentions that Graphical Identification and Authentication (GINA) file changes can affect some third-party programs, such as Symantec pcAnywhere. I use pcAnywhere and implemented Amnon's procedure for changing the logon screen. To save others some time and confusion, I want to share my experience with people who might use pcAnywhere and want to customize their logon screen.
Two types of GINA files exist—authenticator and filter. An authenticator file authenticates the user who's trying to log on. A filter file provides additional capabilities—for example, in pcAnywhere, the filter file adds a GINA filter (i.e., awgina.dll) to provide the following functions:
- support a pcAnywhere host's Ctrl+Alt+Del command handling
- turn off a host's background and screen saver to optimize the desktop
- allow file transfers only when logged on to Windows NT
- authenticate a user against NT's user list when use NT user privileges is selected for callers
GINA files can be chained, and if the chain is broken, you might not be able to get the logon prompt to appear or to function properly.
Different pcAnywhere versions handle GINA chaining in different ways. For example, pcAnywhere 10.5 and later doesn't chain awgina.dll. Therefore, you can follow Amnon's instructions without applying the registry changes I discuss below. However, I recommend you follow my instructions if you're using pcAnywhere versions 9.2 to 10.0.
Win2K pulls the awgina.dll file from the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\Current-Version\Winlogon\GinaDLL registry subkey. This subkey's value should be %systemroot%:\winnt\system32\awgina.dll. The OS then checks the chain for the value HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\pcANYWHERE\CurrentVersion\System\GinaDLL. If Win2K can't find this value, the OS defaults to msgina.dll, which is the default GINA file. But if you're creating a customized logon screen, you want the OS to use the msgina2.dll file that you create. If the string value %systemroot%:\winnt\system32\msgina2.dll doesn't exist, you need to create it. Finally, reboot your computer for the changes to take effect.
If pcAnywhere doesn't respond correctly (e.g., you can't send a Ctrl+Alt+Del command to the host), check the registry values I mentioned. You'll probably find that the awgina.dll file isn't properly chained.