I installed 10.10 2 days back and was facing challenges with the CPU running high on UserEventAgent and temp going high up to 90C. Tried this http://forums.macrumors.com/showthread.php?p=19200839&posted=1#post19200839 and when I rebooted it does not boot. - Stuck at boot logo and after a while the apple logo changes to barred circle. - When entering Safe Mode - stuck as waiting for root device. - With Options key at boot, no Recovery partition visible - CMD+R does not work either. Any help will be greatly appreciated.