Welcome to the Let's Encrypt Community 
No. You must use the ACME protocol to acquire a Let's Encrypt certificate. If you want a super-simple way to acquire a cert in seconds that you can install manually, you can probably use my ACME client that doesn't really require "installing" anything other than one PHP file (you obviously need PHP working):
CertSage has been proven to work both on IIS and on all manner of webservers running on Linux.
For IIS with any ACME client using the HTTP-01 challenge, you will need something like the following file in the /.well-known/acme-challenge directory so that IIS can serve extensionless files (which it won't do by default):
web.config.txt (222 Bytes)
Just drop that file in the /.well-known/acme-challenge directory (you'll need to let CertSage run once and fail for the directory to exist), rename the file to web.config (without the .txt), and try again.