Strange DVD drive issue

My Sony DVDRW drive is connected with the same cable on which one of my harddisk is connected. The issue is that, the drive just doesnt work !.. Then i unplugged my hard disk from the cable so now the only thing connected on that cable is the drive. I turned on my PC and went into bios and viola, i could see my Sony Dvd drive. Then i turned off my PC and connected the hard disk again on the cable so now both the Sony drive and the hard disk are connected on the same cable. I turn on my PC and the Drive disappears. Cant see it in bios or anywhere and when i press the eject button it gives no response. Any ideas what could be the problem? I have tried changing the cable too though.

Edit: Sorry for posting this in the windows forum, i should've posted in the Hardware forum. Mods move it if necessary.

When did it first happen? Were there any updates or programs of any kind installed?

I was trying to fix it and i noticed there was no Jumper.. I probably dropped the jumper somewhere trying to fix it and i couldnt find it. I guess that was the problem. Now what i did was i took out the Jumper from the Hard Disk Drive which was connected on the same Data Cable and i connected that jumper on the DVD drive and made the DVD Drive as Master. Then when i turned on my computer, both the DVD and the HDD are working .

Also, i have a Sata Drive which is not working. I connect it up, and it just doesnt show up anywhere. Not in bios, not in computer management.. No where.. I actually have 2 Sata drives, one of which is connected and it is working. The 2nd one when i connect does not work. Do i have to install RAID or something to make it work ?

Are both SATA drives on the same controller?

It's all about the jumper. Maybe when you plug your DVD drive, you forgot to check if you plug the jumper on slave or there is no jumper at all.

@grishamist
Yeah i dropped my DVD drive jumper somewhere and i cant find it so i removed the jumper from the Hard Disk and put that jumper in my DVD drive to make my DVD drive as Master. The HDD has no jumper.. Now its working.

@Don2007
I actually dont know what controller means? I've connected it to different sata ports, one of them is working the other one just doesnt show up anywhere although sometimes when i touch the Sata Drive while connected im pretty sure i feel the drive spinning or something. Does that mean that the drive is bad?

The controller is the connection on the mother board.

JUMPER!!! I agree that the problem is in jumper. You may make you disc drive a slave in bios and thus resolve.