Well, I just got back from the Apple store and they don't know what the problem is with my iMac and they don't repair or have parts for computers over 5 years old. They said it could be the logic board or something else that could have been lying dormant until now. Not sure what I'm going to do at this point, but it's starting to look like new computer time. I feel bad because everything was going great after the install of the new HD. As soon as I completed the restore with my external HD and Time Machine and had to do a reboot that's when I encountered this problem,which is: the computer will not boot up. It will start up and I hear the chime then I see the Apple logo and the message comes on the screen saying Ineed to restart my computer, hold down the power button,then press the power button again. I tried holding down the C key, then the Option key, then the Shift key and it didn't work. It's as if the computer doesn't recognize the keyboard and as I was trying any of this I inserted my Mac OS X DVD and I can't eject it frm the computer. So, at this point if anyone has any other ideas please let me know. If not, thanks for all the help. This is a great website. Peter