diff --git a/Contrib/System/SConscript b/Contrib/System/SConscript
index 40512458..8c842fd7 100644
--- a/Contrib/System/SConscript
+++ b/Contrib/System/SConscript
@@ -38,10 +38,15 @@ if env['TARGET_ARCH'] != 'amd64' or msvc: # BUGBUG: Call-amd64.S is missing GAS
 			defs += ['SYSTEM_PARTIALCALLSUPPORT']
 	filename = 'Call' + srcsuff
 
+	# When using the MS toolchain, SCons can pass .sx files to cl.exe:
+	# "D4024 : unrecognized source file type 'file.sx', object file assumed"
+	# "D4027 : source file 'file.sx' ignored"
+	# ...and then it returns 0!
+	# This only happens if TryCompile .S fails (ML/ML64 not in %PATH%?)
 	conf = env.Configure()
 	if conf.TryCompile('END', '.S'):
 		files += ['Source/'+filename+'.S']
-	elif conf.TryCompile('.end', '.sx'):
+	elif (not msvc) and conf.TryCompile('.end', '.sx'):
 		files += ['Source/'+filename+'.sx']
 	else:
 		print 'WARNING: System.dll: unable to find assembler for '+filename+'.S'
diff --git a/SCons/Config/ms b/SCons/Config/ms
index 735e6c95..a9d42ba5 100644
--- a/SCons/Config/ms
+++ b/SCons/Config/ms
@@ -242,6 +242,7 @@ def add_file(file, obj_name=None):
 #
 
 conf = stub_env.Configure()
+conf.env.Append(LINKFLAGS = ['/entry:WinMain'])
 
 int64test = """
 #include <windows.h>
diff --git a/SCons/Tools/mstoolkit.py b/SCons/Tools/mstoolkit.py
index d200dc3c..d19ee3e9 100644
--- a/SCons/Tools/mstoolkit.py
+++ b/SCons/Tools/mstoolkit.py
@@ -179,7 +179,7 @@ def win32ShlinkSources(target, source, env, for_signature):
 			# Just treat it as a generic source file.
 			listCmd.append(src)
 	return listCmd
-	
+
 def win32LibEmitter(target, source, env):
 	# SCons.Tool.msvc.validate_vars(env)
 	
@@ -289,7 +289,7 @@ def generate(env):
 	include_path, lib_path, exe_path, sdk_path = "", "", "", ""
 	targ_arc = env.get('TARGET_ARCH', 'x86')
 
-	if os.environ.has_key('MSVC_USE_SCRIPT') and "None" == os.environ['MSVC_USE_SCRIPT']:
+	if "None" == env.get('MSVC_USE_SCRIPT', '!'):
 		for x in ['INCLUDE', 'LIB', 'PATH', 'CL', 'LINK', 'ML']: env['ENV'][x] = ""
 		if not env.WhereIs('cl', os.environ['PATH']):
 			raise SCons.Errors.InternalError("CL not found in %s" % os.environ['PATH'])
@@ -300,12 +300,14 @@ def generate(env):
 		if not sdk_path:
 			raise SCons.Errors.InternalError("windows.h not found in %s" % include_path)
 		sdk_path = os.path.normpath(sdk_path + "\..\..")
-		sdk_path_AR = env.WhereIs('lib', exe_path)
 		sdk_path_LINK = env.WhereIs('link', exe_path)
+		sdk_path_AR = env.WhereIs('lib', exe_path)
 	else:
 		include_path, lib_path, exe_path, sdk_path = get_msvctoolkit_paths()
+		if float(env['MSVS_VERSION']) < 7.0: # Override SConstruct default
+			env['MSVS_VERSION'] = '7.1'
+		sdk_path_LINK = env.WhereIs('link', exe_path)
 		sdk_path_AR = sdk_path + '\\bin\\Win64\\lib.exe'
-		sdk_path_LINK = sdk_path + '\\bin\\Win64\\link.exe'
 
 	env.PrependENVPath('INCLUDE', include_path)
 	env.PrependENVPath('LIB', lib_path)
@@ -327,8 +329,13 @@ def generate(env):
 	env['PCHCOM'] = '$CXX $CXXFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS /c $SOURCES /Fo${TARGETS[1]} /Yc$PCHSTOP /Fp${TARGETS[0]} $CCPDBFLAGS'
 	env['BUILDERS']['PCH'] = pch_builder
 
-	env['AR']          = '"' + sdk_path_AR + '"'
-	env['ARFLAGS']     = SCons.Util.CLVar('/nologo')
+	# VC 2003 Toolkit does not have lib.exe but we can use link.exe
+	if not sdk_path_AR or not env.File(sdk_path_AR).exists():
+		env['AR']          = '"' + sdk_path_LINK + '"'
+		env['ARFLAGS'] = '/LIB ' + env['ARFLAGS']
+	else:
+		env['AR']          = '"' + sdk_path_AR + '"'
+		env['ARFLAGS']     = SCons.Util.CLVar('/nologo')
 	env['ARCOM']       = "${TEMPFILE('$AR $ARFLAGS /OUT:$TARGET $SOURCES')}"
 
 	if 'AMD64' in targ_arc.upper():
@@ -362,8 +369,6 @@ def generate(env):
 	env['REGSVRFLAGS'] = '/s '
 	env['REGSVRCOM'] = '$REGSVR $REGSVRFLAGS $TARGET'
 
-	if not env.has_key('MSVS_VERSION'): env['MSVS_VERSION'] = '7.1'
-
 
 def exists(env):
 	return env.Detect('cl')
diff --git a/SConstruct b/SConstruct
index baf1cf1a..add0f181 100644
--- a/SConstruct
+++ b/SConstruct
@@ -446,6 +446,8 @@ def DistributeExtras(env, target, examples, docs):
 ######################################################################
 
 if defenv['MSTOOLKIT']:
+	if ARGUMENTS.get('MSVC_USE_SCRIPT', ''):
+		defenv['MSVC_USE_SCRIPT'] = ARGUMENTS.get('MSVC_USE_SCRIPT')
 	defenv.Tool('mstoolkit', toolpath = [Dir('SCons/Tools').rdir()])
 
 defenv.Append(CCFLAGS = Split('$APPEND_CCFLAGS'))