C#如何判断系统是否安装了WinRaR

C#怎么判断系统是否安装了WinRaR?
C#怎么判断系统是否安装了WinRaR?我是新手啊~很急在线等！！！

[解决办法]
注册表:
HKEY_CLASSES_ROOT/SHELLEX/CONTEXTMENUHANDLERS/WINRAR
[解决办法]
static public bool Exists()
{
RegistryKey the_Reg = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\WinRAR.exe");
return !string.IsNullOrEmpty(the_Reg.GetValue("").ToString());
}