I downloaded and ran XamarinInstaller.exe on my Windows 7 desktop computer. I pass the first step, which is asking me whether I want to send usage statistics. I then tell it that it is OK to run it as an administrator, at which point the form disappears, never to be seen again. I've looked at the Task Manager, and once I pass the administrator authentication step, two Xamarin installer processes are running. After a few seconds, though, they both disappear from the list of processes.
Any help would be appreciated, as I would very much like to use Xamarin!