The new 4.45 update for Playstation 3 is having some undesirable side-effects, with users reporting issues once the latest update has been installed, with the console failing to launch past the loading screen after rebooting the machine.
It's hard to say how many users are affected by the issue, but there's still enough people experiencing problems that you might want to hold off on updating the console for the time being, at least until it gets sorted by Sony and we know exactly what's going on.
Update
Sony has released a statement regarding the update:
"We're aware of reports that the recent PS3 update (4.45) has caused. We have temporarily taken 4.45 offline and are investigating."