Troj/Gina is a DLL which is a replacement for MSGINA.DLL, the authentication library in Windows NT. It is installed by copying it to C:\windows\system32\newgina.dll and adding the registry key
HKLM\Software\Microsoft\Windows NT\CurrentVersion\
Winlogon\GinaDLL = C:\windows\system32\newgina.dll
Once installed it logs passwords and other information in plain text to C:\543567.tmp.