Need To Replace Some Registry Keys

I have been using a registry cleaner that has removed some system keys. The computer runs most stuff okay, but I am getting some failures on things like the window that used to come up and ask what to do when I plugged in a usb. Researching this is how I found that some registry keys were missing. I have been trying to get to the install / repair the exsisting winows part of the install cd that comes up when installing the program. I did it once before, but haven't been abble to get there again. I am not talking about the first repair options that come up at first, like restore from a restore point or from a system image. It's the one that comes up during the install process where you can choose a drive and format. The repair choice in that section uses the install cd and not a backed up file. The registry cleaner I was using did back up the registry every time it was run, but replaced it with the new back up each time. and the system image was replaced a few days ago, so no help. By the way, I no longer use the registry cleaner