我建了个模块
代码
Declare Function Findwindow Lib "user32" Alias "FindwindowA" (ByVal kkk As String, ByVal kkkk As String) As Long

在窗体建了个timer1

代码
Private Sub Form_Load()
Timer1.Interval = 500
End Sub

Private Sub Timer1_Timer()
Dim dwnh As Long
dwnh = Findwindow(vbNullString, "计算器")
If (dwnh = 0) Then
MsgBox "hahahahaha"
End If
End Sub

我打开了计算器
但他提示找不到dll入口点 findwindowA in user32

Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long

你在声明函数时函数名打错了。"FindWindowA" 和 "FindwindowA" 是不一样的。API函数命名规则与C一样，字母区分大小。

哦
终于能运行了
谢了！～～～～～～～
继续努力去了！～