Optical Disk Drive Letter not detected on My Computer

Hi all,
I was out of city on my business trip, for over more than a month. I just came back yesterday and I tried to insert a DVD onto my computer's Optical Disk Drive. They looked so weird. Since I was not able to find the Drive letter on My Computer Window, I searched for it in the explorer bar.
It was not there, then I consulted one of my friend where he was too not aware of the problem. So really looking out for someone to guide me, to solve the problem. Would like to add a note that my kid was using the laptop in the mean time I was out, so you may let me know the solution in both Hardware and software angle.
Would be very much thankful to hear from you.
