Please do this and you should be fine. After 7 tries this is what I did.
Even though the prescan did not find any conflicting software I went in to msconfig and I disabled all NON Microsoft installed software. Just to be on the safe side I uninstalled my antivirus program, remove anything plugged in via the usb ports then restarted my computer. I started the Windows installation process again and it installed. Maybe about 30 minutes. Don't forget to reinstall your Antivirus program. Until you do though Windows Defender will run at start up.
So far I like the product and is a lot faster than Windows 7.
My system is 64bit, and I installed keeping all personal settings, etc.
Hope this saves you further headaches in the future.