Some of these may seem like common sense but bear with me.
Your usb cable is good?
Are you using a usb hub?
Your machine loaded the drivers for the f4 board when you plugged it in?
It says STM32 STlink when you open devices and printers?
Have you looked around on the ST e2e forum?
I know that there is a STM32 stlink utility you can down load from here:http://www.st.com/in...duct/251168.jsp
The latest usb drivers are there also.
hope it helps