try win32-process gem

lib/middleman/cli.rb

@@ -1,5 +1,4 @@
 require 'thor'
-require 'rbconfig'
 
 module Middleman
   class CLI < Thor
@@ -39,19 +38,14 @@ module Middleman
     def server
       v1_check
       
-      if Config::CONFIG['host_os'].downcase =~ %r{mswin|mingw}
-        ::Middleman.start_server(options)
-        puts "== The Middleman is standing watch on port #{options[:port]}"
-      else
-        if options["livereload"]
-          livereload_options = {:port => options["livereload-port"]}
-        end
-      
-        Middleman::Guard.start({
-          :port        => options[:port],
-          :environment => options[:environment]
-        }, livereload_options)
+      if options["livereload"]
+        livereload_options = {:port => options["livereload-port"]}
       end
+    
+      Middleman::Guard.start({
+        :port        => options[:port],
+        :environment => options[:environment]
+      }, livereload_options)
     end
 
     desc "build", "Builds the static site for deployment"

lib/middleman/guard.rb

@@ -1,8 +1,12 @@
 require "guard"
 require "guard/guard"
 require "guard/livereload"
-require "webrick"
+require "rbconfig"
 
+if Config::CONFIG['host_os'].downcase =~ %r{mswin|mingw}
+  require "win32/process"
+end
+  
 module Middleman::Guard
   def self.start(options={}, livereload={})
     options_hash = ""