Hi, I have exactly the same problem as you. Both drives showing in the bios both showing in the device manager list but with an exclamation mark but not showing in My Computer.
I had to replace the power supply in my computer and ever since I have had this problem with the dvd drives not showing. It seems very unlikely that they both broke at the same time that I changed my power supply.
Im probably gonna have to take it to a computer repair shop.
Good Luck