Hello BC11 ,
Start and Right click on "My Computer" and select "Manage."
From the "Computer Management" window select "Device Manager" from the list on the left.
From the device list, expand the "DVD/CD ROM" category by clicking on the [+] symbol found to the left. If the drive is detected by the system, there will be an entry for your external drive (Memorex).
Right click and select "Uninstall". Restart the computer. Doing so will reinstall the necessary drivers, letting you know if you had a software issue.
If it is not listed under "DVD/CD ROM drives," expand the "Other Devices" category and see if there is an entry for an "Unknown Device."
Right click the "Unknown Device" and select "Properties."
Under the "General" tab, check for the Device status (error codes).
If no error code found, unplug unit and restart the computer.
Once your system is up, connect your unit. Doing so will reinstall the necessary drivers, letting you know if you had a software issue.