Turn on the usb debugging option of Nexus S.
Install Google Android usb driver.
Reboot PC.
http://goo.gl/JiWSJn
https://developer.android.com/sdk/win-usb.html
Install Adb and Fastboot.
http://goo.gl/y3Yc25
Install Cyanogenmod.
http://wiki.cyanogenmod.org/w/Install_CM_for_crespo
http://heisvoid.blogspot.kr/2012/06/how-to-flash-custom-rom-on-nexus-s.html
Install Google apps.
http://wiki.cyanogenmod.org/w/Google_Apps
