I've just been leafing through MSDN, and found this page
Breaking Changes in the Visual C++ 2005 Compiler (C++)
Apparently a lot of redundant features were removed in VS2005, with the single threaded runtime libraries seeming to be being one of them.. in other words, it would appear you're already using the multi-threaded runtime libraries.
Another option which appears in the C/C++ tree is called
Command Line - does this appear in VS express edition?