判断是否在VB5环境下运行 
声明：
Private Declare Function GetModuleFileName Lib "kernel32" Alias _ "GetModuleFileNameA" (ByVal hModule As Long, ByVal lpFileName As _ String, ByVal nSize As Long) As Long
函数：
' True 表示在 VB5 环境下运行
Function IsRunUnderVB5() As Boolean 
Dim S As String, Length 
Length = 256 
S = String(Length, 0) 
Call GetModuleFileName(0, S, Length) 
S = Left(S, InStr(S, Chr(0)) - 1) 
IsRunUnderVB5 = UCase(Right(S, 7)) = "VB5.EXE"
End Function