Add-Type @"
    using System;
    using System.Runtime.InteropServices;

    public class User32 {
        [DllImport("user32.dll", SetLastError = true)]
        public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

        public const uint WM_KEYDOWN = 0x0100;
        public const uint WM_KEYUP = 0x0101;
    }
"@

# Set the title or class name of the target window
$windowTitle = "Your Window Title"

# Find the target window
$windowHandle = [User32]::FindWindow([NullString]::Value, $windowTitle)

# Check if the window is found
if ($windowHandle -ne [IntPtr]::Zero) {
    # Send a key press (e.g., the 'A' key)
    [User32]::SendMessage($windowHandle, [User32]::WM_KEYDOWN, [IntPtr]'A', [IntPtr]::Zero)
    [User32]::SendMessage($windowHandle, [User32]::WM_KEYUP, [IntPtr]'A', [IntPtr]::Zero)
} else {
    Write-Host "Window not found."
}