But of course! Thank you. Forgot to check the jumper, which was on the replacement HD but not on the original at all. Checked the settings, removed the jumper, and all is right with the world. The OS is installing as I write these words. Again, many thanks. Tom B. On 9/22/07 11:05 PM, "Roy Hackett" <newthings at earthlink.net> wrote: > Tom I think you have a master/slave conflict between the HD and the > optical drive. I think the CD needs to be master and the HD a slave. > Check the jumper setting on the old HD and duplicate on the new. > Roy