|"It's a SATA. Do SATA drives have a master/slave?"|
Check your SATA data cable, and SATA power cable to the DVD combo drive - see my info in Response 1. If in doubt, use another data cable or power cable.
"Also I tried to boot from a disc... failed."
You should be able to boot the computer from a bootable disk in an optical drive even if something's not right about the data on the hard drive.
Your settings must be correct in the mboard's bios, in your Boot Order or similar settings - CD drive or similar must be listed before (above) any hard drive - but it doesn't necessarily have to be listed first.
If you are using a drive controller card
- CD drive or similar must be listed before SCSI or similar.
- if the optical drive is connected to a drive controller card in a slot, not to the mboard SATA,
- some drive controllers do not support the ATAPI standard, which supports optical drives
- you may not be able to boot from a bootable disk in an optical drive when it's connected to a drive controller card in any case - if you have SATA built into the mboard, connect it to a SATA header for that.
If you have more than one optical drive (CD or DVD drive) many bioses will only boot from a bootable disk in ONE of the optical drives. In that case, find the list of optical drives in the bios - the one you want to boot a bootable disk from must be made to be first in the list, Save bios settings.
Make sure you do not have a flash drive plugged in while booting. Some bioses will attempt to boot from a flash drive, according to bios settings regarding booting from USB or removable devices if that's listed before a CD drive or similar, or regardless of bios settings if removable devices is listed before a CD drive or similar. If the flash drive is not bootable, the bios may not try to boot from anything else.
Some older mboards that support SATA specs (150mb/sec max burst speeds) but not SATA II specs (300mb/sec burst speeds) have two types of SATA headers - one type you can boot bootable hard drives or bootable disks in optical drives from, the other type you cannot boot those things from. If that applies, that situation is specified in the Dell Owner's or User's manual, and in the Service manual.
Search the web for: Inspiron 530 Service Manual
and you'll probably get a"hit" that is the Dell info about the Service Manual.
Can you install the DVD combo drive in another computer to test it ??