My Mistake
I forgot to inform about the other items. I use two external HDDs'. One as the Time Machine back up and the other for storage. Lots of pics and video. Anyway, here is the equipment - When I try to install Win7, I un-plug the the 2nd monitor, the storage drive and all other USB items. I do have the optical drive and, of course, leave it connected. For the support software I use a 64G USB drive and place the Win7 cd into the drive. Then activate Boot Camp and follow the on-screen instructions. All seems to go ok - Macintosh HD partitions correctly (at least I see no errors). Just before "Boot Camp" drive is created, I am informed that an adjustment needs to be made to the USB drive. Then white screen, black screen, Mac sign on jingle and..........nothing. Then a black screen and I am informed that boot mgr could not be found. Insert boot able media and press enter. But nothing happens. All the needed software is already in. Then I have to shut down, hold the option key and turn the computer on. Then select Macintosh HD to use the iMac again. I have even tried selecting the Windows cd symbol and pressing any key immediately after. It "locks up" again. If I am not telling you what you need to know, let me know. I have had the iMac for almost a year and have learned a lot but a LOT to go. Thanks for your help and patience.