1. Start the computer and hold down the DEL or F 12 key until the BIOS setup window (usually with a blue background and yellow English words) appears.

2. Select and enter the second item, "BIOS Settings". Find the entry or group containing the BOOT text, and find three entries "first", "secend" and "third" arranged in sequence, representing the first boot, the second boot and the third boot respectively.

Here we can set it to CD-ROM drive, floppy drive and hard disk in turn. (If you don't see these three E's on this page, the option menu on the right side of the boot is usually "Settings", and you can see them by pressing Enter. You should select "the first one" and then press enter, and select CD-ROM in the submenu that comes out. Press enter again?

3. After selecting the startup mode, press F 10 to open the E-text dialog box, and press "Y" (which can be omitted) to enter, and the computer will automatically restart, which proves that the changed settings are effective.