|You need to tell us what the make and model of the external hard drive is. |
If you DO NOT have any software that is simulating a virtual CD or DVD drive installed in Windows on your internal hard drive(s), then....
Your situation is probably similar to the one about the Hitachi LifeStudio external hard drive I referred you to.
The hard drive has a small partition on it that has software on it that results in you seeing a virtual CD or DVD drive, ONLY when the external drive is plugged in, and ONLY when the external drive enclosure's circuits are being recocognized properly and ONLY when the external drive is actually getting 500 ma from the USB port it's plugged into.
Is that virtual CD or DVD drive appearing ONLY when the external drive is plugged into the computer ??
The rest of the drive's space has a partition on it on which you store data.
When the drive was new, you were seeing BOTH of
- a drive letter in My Computer or Windows Explorer for a virtual CD or DVD drive,
- AND another drive letter for the data space on the drive
It's very common for people to unplug an external hard drive (or a usb flash drive, or a memory card) while Windows is running WITHOUT clicking on the Safely Remove Hardware icon and choosing to STOP accessing the drive. When they have neglected to do that, sometimes, but not always, data is DAMAGED on the hard drive inside the external hard drive's enclosure.
The effects of that data damage vary.
In the case of the Hitachi LifeStudio external drive, he can see the virtual CD or DVD drive, ONLY when that external hard drive is plugged in, but he can no longer see the drive letter for the large data partition on the externl hard drive that he could see before, in Computer (in Vista or Windows 7) or in My Computer (in XP and previous, or in Windows Explorer .
If you examine the external hard drive's space in Disk Management as I described at that link about the Hitachi LifeStudio external drive I referred you to, and tell us what it says for what is on the external drive's space, we can confirm whether there's evidence data on the drive has been damaged.
In XP, to go to Dislk Management, you can either
- Click on Start - Run - type: diskmgmt.msc (click on OK or press Enter) .
- or - click on Control Panel - Classic view - Administrative Tools - Computer Management - Disk Management (on the left side of the Computer Mangement screen).