Which operating system are you using?
Does the drive show up in the operating system (like in My Computer in Windows XP)?
Normally I'd advise someone to set up the boot order of their computer to allow booting up from the optical drive first. Boot order is set in the bios...look in your manual for how to get into the bios and set this up.
Then try to boot from bootable disk, like the Ultimate Boot CD: http://www.ultimatebootcd.com This will test to see if the drive can function outside the operating system.