So I built my computer about a year ago and have had no problems with my drive which is a plextor 712-A. Anyway one day when i was using the computer the drive stopped reading the disk that was in the drive. On the my computer screen it shows the drive and has a generic disk icon but when clicked on shows the drive as being empty. I realized that if i restart the computer it will detect the disk in the drive and use it normally but if the drive is opened and and then closed again with this disk or any other it will fail to read it further. I have downloaded new firmware and rechecked all the cable connections. I suspected the drive may be defective so I put in a different drive and it has the same problem. I am at a complete loss as to what is wrong. Any help is greatly appreciated.