You can do it - but it's not a good idea:
Process[] processes = Process.GetProcessesByName("chrome");
foreach (Process p in processes)
{
p.Kill();
}
You would have to repeat this for IE, Firefox, opera, etc., etc..
But...if your app did that on my PC? It would be deleted with extreme prejudice, a refund would be demanded immediately and I would never trust an app from your company again.