I have a tower running Win 7 and CD/DVD player comes up in Device manager with a yellow exclamation. I downloaded the latest driver from the manufacturer but that didn't help. It will not show up in My Computer or Explore. I replaced it with a new DVD/CD player and it did the same thing. I connect an external dvd drive via USB abnd it does the same thing. I switched the SATA connections with the hard drive and it still does the same thing. Any ideas why this is happening and how to resolve it?