Throughout boot process, PC utilizes data found in something called BIOS to decide what to load first. BIOS is little part of software stored on a chip that decides what PC can do without accessing other programs. It is BIOS that tells PC to load OS from hard drive when start PC.

If you are having problems with OS or you want to install a new, you can tell BIOS to avoid hard drive and boot with CD drive when PC starts. BIOS may vary a little based on company, but you can usually select to boot from a CD drive, floppy disk drive or hard drive. Few new BIOS also have capability to boot from a flash drive.

Instructions

Step 1

Turn on PC. Observe screen as it is booting up and get message "Press F12 to enter setup." The key differs based on PC Company. When you see that message, start tapping proper button on keyboard until it loads Setup menu.

Step 2

Make use of arrow keys to highlight "Boot" option from BIOS menu and push "Enter."

Step 3

Choose "Boot Device Priority" and push "Enter."

Step 4

Push "Enter" on option that says "1st Boot Device." Make use of arrow keys to choose "CD ROM" from menu and push "Enter" again.

Step 5

Push "F10" to save settings and exit BIOS menu. PC will keep on to boot up. Put in CD in disc drive when prompted to boot from a CD.