When installing Windows 8.1 Microsoft have made it look like you need a MS Live account during the installation and doesn't proceed unless you either create an account or enter in your current details.
Well don't despair there is a way around this:
At the windows asking you to enter in you Live account details click on the "Create account link" and then click "Sign in without a Microsoft Account".
If you still have issues, disable your Internet connect and try the above again.
I hope this helps.