Try forcing DFU mode.
Plug your ipod into your pc.
Hold the sleep button (power button) and Home button for 10 seconds.
Then release the Power button but keep holding the Home button until your PC states "Found New Hardware". Then you should be able to restore it. If this doesn't work let me know.
Ok, the fact its blank is a good sign. Did you keep the home button held down when you got a blank screen? Keep a hold of it if you didnt. If this doesn't work google TinyUmbrella and download it, run it with your iPod plugged in and see if you can click "enter recovery mode". Then restore from there.
Let me know what happens.