@nexusplz, thankyou for all your findings and feedback on this thread, had the same problem as all here. I have a nexus s and up until this morning all was fine. Had to restart my phone for my operators updates and that was it, I was stuck with the google logo and the soft keys lit up. Connected to the phone via SDK and PDA drivers but could not get any communication. I returned to the recovery screen just looking for options, had a browse through the SD card looking for any kind of file that may help, unable to find anything I backed out of the SD card back to the recovery screen and went for a random reboot. Still dont know why but it worked! A total of 2 hours and about 20 - 30 reboots. Just to confirm my battery was never low, and once rebooted battery was at 77%. I intend to look at rooting now as 2.3.4 seems a little 'iffy'. Thanks again for your input in to this thread.