I'm not new in Ubuntu, but I'm trying to install Ubuntu on another computer (my sister's PC), but when I configure BIOS to load from optical drive, it never loads.
Actually, Windows loads!
If you can boot from your Ubuntu CD on another PC, it seems to be a BIOS or CD-ROM matter. So, you have two options:
try to make the PC boot from CD - re-check if the BIOS has the required boot order, or try to open the boot device menu that's usually available besides the BIOS (with AMI BIOS: called BBS POPUP, activate by pressing ESC during boot).
try to use another boot device - a USB stick, for example (again, make sure that booting from USB is enabled in the BIOS and that the boot order is set appropriately).
