Android Nexus S Boot Freeze My Android Nexus S does not boot anymore.
If I start it normally, I get a screen like the following and it won't ever change (tried for hours):



I can still go into the boot loader with PowerOff + Volume Up, if I try the RECOVERY option, I just get a screen that looks like this:



Does anybody know how to install the original google android again, or at least flash it with a similar operating system?
If you don't mind to end up with Cyanogenmod9 (Ice-Cream-Sandwich):

Here's the full update guide from CyanogenMod's Wiki:
http://oldwiki.cyanogenmod.org/wiki/Nexus_S:_Full_Update_Guide  

Here are builds (go for release candidates or stable builds for CM9):
http://get.cm/?device=crespo  

Recovery images are here:
http://www.clockworkmod.com/rommanager/
flash via 'fastboot flash recovery [recovery.img]