Problems reinstalling Snow Leopard OS

I am selling a 2010 Macbook Pro that doesn't have a functioning optical drive. I have used the remote install system to load my original installation disk on a PC and connect to my Macbook. It seems to be working, as I can now access the install disk from my Macbook. However, I cannot reboot from the installation disk. I have tried to shut down, then press "C" at the chime, but the computer just continues to load normally. I have also tried holding "option" but I only get the option of booting through the regular Mac HD. I'm not sure how to troubleshoot from here.

Thanks!