如何确定给定的软件是否已安装，如果未安装，如何使用PowerShell进行安装？

$softwareName = "软件名称"
$regPath = "HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall"
$softwareKey = Get-ChildItem $regPath | Get-ItemProperty | Where-Object {$_.DisplayName -eq $softwareName}

if ($softwareKey) {
    Write-Host "软件已安装"
} else {
    Write-Host "软件未安装"
}

$softwareName = "软件名称"
$installPath = "C:\Program Files\软件目录"

if (Test-Path $installPath) {
    Write-Host "软件已安装"
} else {
    Write-Host "软件未安装"
}

$installerPath = "安装程序路径"
$arguments = "安装参数"

Start-Process -FilePath $installerPath -ArgumentList $arguments -Wait