Not able to access Dell External HD

Hello,

I was using Dell External 2 TB hard disk, and sometime before I couldn't access it. When I try to connect it the light turns on and disk is shown as a DVD icon (yeah, it is strange) also I checked with Computer management to see whether it detects the Ext. Disk or not. Fortunately available space of the disk is visible and not the disk on the list.

Problem listed (as simple)

1. Ext. Hard disk icon in my computer visible as DVD drive and it is not accessible.

2. On Disk Mgmt, I could see the available space of the Ext, Disk on the down but not on the list above.

Please let me know if any has some solution to overcome this situation.