Quite a few PS3 users are having extreme difficulties using their PS3's after upgrading to Sony's latest firmware which was only suppose to remove the other OS feature.
Sony released new firmware for the PS3, for "Security Reasons" that is, that removed the “install other OS” option and locked out people who used another platform through dual-booting.
A quick glance at the official PlayStation forums you will see users complaining about not being able to log into PSN or load a disc after installing the update.
There was even one complaint about not being able to turn on their PS3 at all.
GOOD JOB SONY!