DVD on Dell 8100 Failing

My Dell 8100 includes a fixed 8X Internal
CD-RW/DVD Combination Drive-Factory Installed.
Total hours of use would be 50 hours and I play
DVD’s on the 8100. After one year of great service
my DVD’s will not open; the message” Put Disk
in Drive “D” remains on the screen, and the
noise from the DVD drive is an attempt to open,
and I can hear the spin but nothing plays. I was
thinking the laser is defunct, but have I missed
any steps ? tested Device Manager,Drivers,etc.
and they are working properly. Any ideas from the
technical Dell repair group ?

Thank you,

Greg Warren