Remote Install Mac OS X Problem

As my mac mini's super drive malfunctions(fail to read frequently, vibrating with noisy while reading), I cannot use the super drive to reinstall my mac mini. After googling, I found that the re-installation could be done via Remote Install Mac OS X on my PC. I followed the instructions e.g. hold down Option (alt) key while restarting mac mini. However, it does not show a list of available startup disk and it just goes to the login screen.

My config and setting:

PC:
I selected "Ethernet" as the network connection in Remote Install Mac OS X;
I have checked "Enable DVD or CD Sharing" on my PC(Win 7 64 bit SP1);

Mac:
All the I/O devices(keyboard, mouse and monitor) are non-apple products.
Mac Mini is a Mar-2009 and non-server version.
OS: Snow Leopard 10.6.7

If I don't want to use an external DVD drive, does anybody tell me how to do it via Remote Install Mac OS X?