I agree with augie44's reply but additionally suggest you remove all non-Microsoft drivers before updating to Win 8.1. For example, I have Asus motherboard related drivers I skipped. I just took whatever the Win 8 full install gave me. Also disconnect any additional peripherals, if you have any, before the Win 8 install. All these can be added back after updating to Win 8.1.
Good luck.
David B.