Sony has released a new PS3 firmware update designed to resolve issues experienced by a "small number" of users following last week's 4.45 update.
Firmware 4.46 fixes an issue caused by last week's update causing some PS3 users' consoles to brick. If that was you, you'll need to download the firmware update via your PC, transfer it onto a compatible memory stick/card and install it via the PS3's Safe Mode.
Full instructions on how to enter Safe Mode and install the update can be found on Sony's website.
Sony pulled last week's 4.45 update following reports from users stating that the update had caused their console to become unusable. The firm later said that it had "identified the issue" and "apologise[d] for the inconvenience".