Please start at the top and do all of these even though you have done some before as it is often the
total process which solves the issue.
Try this - Control Panel - Device Manager - CD/DVD - double click the device - Driver's Tab - click
Update Drivers (this will likely do nothing) - then RIGHT CLICK the drive - UNINSTALL - REBOOT
this will refresh the default driver stack.
Then work your way through these - remember the drive could be bad, could have a loose cable or
slight corrosion on the contacts (usually for a laptop) and other issues.
Another possibility is that the cables are loose. Remove ALL power, then check cables in both
ends. Remove and replace, do not just snug. For laptops you can often clean the power and
data contacts with a pencil eraser.