回複：回複：U should move the order of CD ROM before the hard di

Look like the BIOS did not detect the CD-ROM. Does the BIOS and POST detect the floppy drive? If you are sure that the CD-ROM drive is working and the connection is fine, you might want to flash BIOS. Go to support.dell.com to download the BIOS for Dimension 9100 and boot to floppy to flash the BIOS.