If the drive is seen in the BIOS, and that computer can boot from a CD/DVD when you're using the HP drive, but not the Sony drive, then the Sony is not able to read the disks. The "working normally" report in Device Manager means Windows can communicate normally with the drive's electronics. But Windows isn't involved when booting anyway, so we can conclude the drive isn't reading anything off the disks. The laser has probably failed, but a dirty laser lens can cause the same symptom, so if you haven't already tried cleaning, give it a go. If it gets it going, good, otherwise bin it.
Just as an afterthought, the jumper settings will only work if set correctly, but sometimes two drives just don't get along - have you tried the Sony alone as Master?
Edited by Platypus, 10 January 2009 - 03:36 AM.