Currently I have dual boot of Windows 7 32 bit and Windows 10 64 bit. Now I want to upgrade windows 7 32 bit to 64 bit and I have to clean install Windows 7 64 bit. As far as I know after clean installing Windows 7 64 bit, I will be unable to load windows 10 64 bit. Is there any method that I dont have to reinstall windows 10 64 bit and the dual boot of windows 7 and windows 10 64 bit works again. Writing a new boot record will enable the dual boot again or not?? or is there any other method?