Giant pain in the ass! Every apparent work around had negative consequences (really hating UAC, etc...)
Here's the way to install it initially with a local account to keep your old login/password:
After you install Windows 8.1 and you are asked to sign in to a Microsoft Live account, there's no apparent way to move past that screen if your intention is to only have a local account. Here's the trick: Click the Create New Account link and then at the bottom of that next screen you will see a link that will let you cancel the process. You will then login using your local account.
I went to (tying to remember, I’m on an xp mch at work) pc settings and then skydrive. You can, as far as I can tell, tell it to not use skydrive for cloud storage and/or syncing data between microsoft devices.
You can boot the pc without having an internet connection, so I am not sure if you even need a microsoft account?
It has been rumored that when Bill Gates started dating he would tell of his aspirations of starting his own software company someday. One night while on a “conquest” he asked his date if she could help him come up with a name for his potential company. She supposedly looked down and said how about micro soft?