U should move the order of CD ROM before the hard disk

you may try to use +/-, or pageUP/PageDown to change the order of the sequence or up-arrow/down-arrow.

You don't need to format the disk before the re-install and just let the installation procedure format. When you are at the step to select disk (you should see it if the disk detected during self-test), you will see the disk, please delete the partitions and re-create the system partition, and u may pick "fast format" to save time, and install.

你是天吓论坛的安和吗？