This has been a common problem the last few days. I was under the impression that has been fixed - I downloaded the exe and started and got to the first page.
But, hm, I tried Developer Edition, and you are downloading Express. Did they forget to check that one?
Anyway, try this in an elevated PowerShell Window:
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type Dword
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type Dword