Install Windows On Old mac

To install Windows on a late 2006 iMac, you cannot use modern Boot Camp Assistant and require a 32-bit version of Windows or a specially patched ISO for 64-bit Windows. You must create a bootable Windows DVD by first patching the ISO using a tool like the Windows 10 ADK, then booting from this DVD by holding the Option key during startup. You will need to download the appropriate 32-bit drivers or use the drivers provided with a 32-bit Windows 7 or 8.1 installation. 

1. Prepare Your Windows Installation Media 

• Obtain the Windows ISO:You’ll need a 32-bit version of Windows (e.g., Windows 7 or 8.1) or a 64-bit Windows 10 ISO that has been patched for 32-bit EFI systems.
• Patch the ISO (for 64-bit Windows):
  • Download and install the Windows Assessment and Deployment Kit (ADK) on another computer.
  • Extract the contents of your Windows 10 ISO to a folder, for example, c:\temp\win10.
  • Open the Command Prompt, navigate to the Oscdimg directory within the ADK, and run the oscdimg command to create a modded ISO file. For example: oscdimg.exe -n -m -p00 -bc:\temp\win10\boot\etfsboot.com c:\temp\win10 c:\temp\output\modded.iso.
• Burn the ISO to a DVD:Burn the (modded) Windows ISO to a blank DVD-R using a DVD burning application.

2. Boot from the DVD

• Insert the DVD: Place the Windows installation DVD into the iMac’s internal DVD drive. 
• Boot Holding Option Key: Restart your iMac and immediately press and hold the Option (or Alt) key on the keyboard until you see a window showing available startup volumes. 
• Select EFI Boot: Select the option for the Windows DVD from the boot menu. You may need to try selecting the option a few times. 

3. Install Windows

• Follow the Windows Setup:Follow the on-screen prompts to install Windows. You may need to format the hard drive. 
• Install Drivers:After the Windows installation, you will need to manually install drivers for your hardware.
  • Download the latest Windows support software (drivers) from Apple for your specific iMac model. 
  • Install these drivers from the downloaded Boot Camp folder.