I was able to figure out what causes my computer to freeze.
Every night, I used to turn off my computer and my battery backup/surge protection unit. It would also turn off my Samsung printer connected with a USB cable.
Every morning, I used to push the power button "on" for the UPS unit, and my computer, along with the printer, would start.
Somehow I've noticed that my computer used to freeze when the printer was making its regular noises at a boot-up. After "restart", the computer would start normally, without any issues. Why? The printer was already "on" (not going through its start-up procedure).
I unplugged my printer, started the computer, and all my computer start-up freezing problems were gone.
Right now, I turn my printer on after the computer's startup process is complete.
I don't know how to permanently fix it, but I know how to live with that "chronic" disease.