I found the fix on the web
After looking around on the web for answers I found this and I got the drivers to install. it is strange that Apple appears to not ever acknowledge the issue at all and it appears that several people have hit this issue.
Click
start (or the windows icon in the lower left of your screen)
Then go to
all programs
Then go to
accessories
Then
right click on command prompt and choose run as administrator
The commands you want to enter are:
D: then press enter
To get the next parts to work it is best if you have "show file extensions" and "show hidden files" turned on so you can find the file to figure out the path.
Now the file you are looking for is called "BootCamp64.msi". There is a file at the root level of the folder that is next to the setup.exe with the same name but it is a .xml, that is not the one you need. In my case the file was in another folder.
The path I used for a thumbdrive install was (as I typed it in to CMD)
E: WindowsSupport\Drivers\Apple then press enter.
If you working of a CD/DVD copy you might need to figure out the path but the file ends with .msi and it will be in a folder called Apple that is in a folder called Drivers
Type in
bootcamp64.msi then press enter
This should open a installer and install the drivers to get Winblows going.
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Sounds like your iMac isn't x64 compatible. Perhaps go with Windows 7 x86?
I have a iMac24 Intel 2.66 and I installed the 64bit version of Winblows7. it should have worked. I discovered that a lot of people have hit this issue.
This is a reinstall after I did something stupid. it worked fine in the last install.