Here is my suggestion. Some may come in and strongly disagree but it's worth trying.
Win10 handles platform changes better than any other version of windows. So here is what I suggest. First, back up any important files. All those family photos, prior tax returns, etc should go on a thumb drive or a spinning disk that isn't attached to the system. Then make the win10 install files just in case. Once you've got everything backed up go ahead and do the swap. Pay attention to drive order as they plug into the old board.
When you put the new board in, make sure to attach the drives in the same order. Then give it a shot. At best it will take awhile and finally work. At worse it will try and fail. If it works, use it for a week and make sure it's all good. If you encounter any errors you can't fix by updating drivers go ahead and reinstall. Trying doesn't take a lot of time and might work. If it doesn't, at least you have the backups so you don't loose any important data. Windows doesn't REQUIRE you to reinstall. I have done myself platform changes and seen it work.