reinstall mac with boot camp

1. After press Command+R or Option to restore MAC from internet, check whether it's latest version and whether boot camp assistant is ready.
2. For Disk Utility, can show all device and make partition if there's some space cannot be found
3. Need copy the driver to the start-up USB Disk and need install from boot camp assistant
4. Can use NTFS for MAC from paragon if necessary.
5. If Windows 7 cannot install on that driver, can format and install

Now the issue is that although windows option is available from Mac, Mac is not an option from Windows bootcamp, it's ok as can press Option to choose.
Another issue is that the mac keyboard cannot be identifier, luckily I have an external keyboard.

Update: it turns out the keyboard's battery is dead, after replacing new battery, it's able to find it by remove the unknown device and add device (need input the number).
For the mac start option, it's caused by APFS system.

Can download windows 7 from these position, shasum is good:

https://www.cnblogs.com/mq0036/p/3492025.html

It's pretty fast

Windows 7 With SP1 64位英文旗舰版
ed2k://|file|en_windows_7_ultimate_with_sp1_x64_dvd_u_677332.iso|3320903680|743598C64E635C72964CF02A3E0AD547|/
下载后请先校验文件（为什么要校验？怎么校验？），
文件名 en_windows_7_ultimate_with_sp1_x64_dvd_u_677332.iso 
SHA1: 36AE90DEFBAD9D9539E649B193AE573B77A71C83 ISO/CRC: 992B8FCD