以编程方式限制Windows 7上的任何应用程序的CPU使用率?

I'm looking for a way to limit the CPU usage by any application on Windows 7 to 50%. I've tried searching the Internet for a way to do this, and it looks like this is an easy thing to do on Linux and Mac OS X (one command in the terminal) but I'm not sure how to do it on Windows 7. Any help would be much appreciated. Thanks!I'm looking for a way to limit the CPU usage by