are u using win 7 x64?
flasher doesnt work with it
then restart ur pc, press f8 before you see the windows logo, choose "disble driver signature enforcement" then open start menu, search/run "cmd"
this is the cute for the 64bit version
but if u've wasted one usb slow, then next time, u need to connect to a different slot.. coz the drivers for the previous slot are already installed..
jus..
change the usb port/slot.. whatever