Installation of Win10 on MacBook4,1

The simplest answer is to install 32 bit Windows 7 with SP1 and then upgrade to 32 bit Windows 10. I say this because Apple officially supports 32 bit Windows 7 on your model Mac. Although Apple does not officially support Windows 10 for your model Mac, upgrading to 32 bit Windows 10 from 32 bit Windows 7 is should be supported by Microsoft. The Windows Support Software (the drivers) can be found by following the links on the Apple webpage Install Windows 7 on your Mac using Boot Camp. I believe the correct link should lead you to Boot Camp Support Software 4.0.4033. You will probably need the optical drive to be working in order to install Windows 7 by using the Boot Camp Assistant application. If the optical drive is not available, then read the other pertinent options given below.

Window 7 can be purchase rather cheaply. For example, this retailer offers Windows 7 Professional 32/64bit Download for 19.50 USD. You may still be able to upgrade to Windows 10 for free. See this article for details.

Your Mac has a 64 bit processor with 2 cores (Core 2 Duo). If you want 64 bit Windows, then there potential problems you may need to overcome. Some of these problems and possible solutions are given below.

• According to Microsoft, you will need at least 2 GB of memory.
• If your Windows 7 media does not include SP1, then you should get a newer ISO file from the Microsoft website Download Windows 7 Disc Images (ISO Files). The download is free, but you will need to enter your Windows 7 product activation key to enable the download.
• The current version of Windows 10 can found by clicking on this link. Note: the link is dependent on the browser you are using. In other words, Safari will goto a different website than Microsoft Edge goes to. While the download is free, you may still need to buy a license key to continue using Windows 10.
• The Window Support Software may not work with 64 bit Windows. See the question Using Boot Camp Support Software 4.0.4033 to install 64 bit Windows 7, 8 or 10 for installation instructions.
• Some 64 bit Windows installation configurations can both BIOS and UEFI boot. However, some early Intel Macs can not handle this type of configuration. If you have this problem, then you will need to remove the UEFI boot files. See the question “Select CD-ROM Boot Type:” error during Windows install for instructions.
• The newer versions of macOS automatically install firmware updates. If you are running an older version of macOS (OS X) then you may need to manually install firmware updates. See About EFI and SMC firmware updates for Intel-based Mac computers for more information.
• If you do not have a working optical drive, then you can try installing Widnows by using the rather complex method described in the question No bootable device USB 2.0 MacBook Pro mid 2014.
• User have reported being able to install Windows by using a flash drive. In my opinion, your Mac is to old, but I will include the following link anyway: Bootcamp - No ISO Option.