unroot help asap

I tried to unroot my nexus s and for some reason i got to stock rom and kept bootloader unlocked and when im on stock rom only the menu soft key lights up and works and also i cant get it to do system update or get sim card recognized so cant use it as phone and not sure if wifi is workig either if someone could either mail me tinybatman@hotmail.co.uk asap or reply here or both

also airplain mode keeps getting activated with out pressing it

thnx

Dan