PS3 Slim stuck on "Connect the controller using USB cable, then press PS button" screen

Solution 1:

It's very simple.

Just connect your controller to the console with a USB cable. Once the console detects the controller, it will move to the next screen, which is the software installation. Keep a pen drive loaded with the latest PS3 console software. Insert the same in the USB slot. Now just follow the on-screen instructions to install & load the PS3 console.