SATA DVD Drive Stopped Working on DVDs, Works for CDs Only

I've had my machine for 2 few weeks now and have had no problems watching and ripping CDs or DVDs to my hard drive. Tonight, I tried to watch a  DVD and it would not recognize that there is one in the drive. I tried several DVDs.  CDs work fine. I removed the driver and re-installed several times.  I've rebooted over and over.  I tried to run the diagnostics by pressing F12 at start-up and it does not work. It took 12 reboots and pressing F12 a million times just to get to the diagnostic menu - one time it got that far then restarted anyway, every other time it just doesn't accept my entry. I got to scroll down to the correct drive one time and select it, then the computer rebooted again on its own. Other then that, the computer operates fine and isn't freezing. 

To top it off, I can't use Dell technical support because I bought this refurbished and it was evidently manufactured in Canada, so no one on the phone or email can recognize my system, since I'm in the US.  It's totally useless to try to get help there, so I'm hoping someone can help me. I can't believe how bad the customer service experience has been.  I spent hours on the phone to India just trying to get the correct OS disc that was not sent with my computer last week. They needed to recognize my system and couldn't find the specs, even when I offered to forward the email from Dell to them.  All I needed was a disc!  I will never buy Dell again or let anyone I know buy it unless someone from the company resolves this ASAP.