I'll try to be brief.
1st, I didn't see a topic dealing exactly with my problem. So here goes.
I bought an Inspiron 15 laptop w/o an OS, and the optical drive didn't work. The seller made me aware of this and said I needed to buy an external optical drive to install Vista. He gave me the Vista install/repair disk (and the drivers disk).
While I was waiting for the optical drive to be delivered I loaded Ubuntu from a disk I had made. Don't ask me why the Linux disk would work using the internal drive but the Vista disk won't. Baffling.
So I recieved a new external optical drive and went to work on installing Vista over the Linux OS. I erased the Linux 1st. Then tried to install Vista, but no matter what I did (changing the boot order etc) the laptop doesn't "find" or "see"an OS to install. In other words I can't boot it up with the Vista OS disk using the external drive.
I can provide any details you may need. Fortunately I also have a desktop computer to work from.
Thanks in advance.