Hi Michael, I have investigated the inability of the asus laptop U43F to upgrade to windows 8.1 with both Asus and Microsoft. My conclusion is to wait a while and see if either one has a work around software solution for the upgrade to 8.1. My U43F works great with windows 8.0 and has not problems with drivers or other hardware issues. After more that 20 hours on the phone with remote access to my laptop and escalated to the highest level of the Microsoft support team, they came to the conclusion that this model will not upgrade to windows 8.1. If you look at Asus's web site, not all their computers are listed as compatible with windows 8 including our model. Asus was in the dark about this issue until I was able to find an upper management support person at Asus who concluded that this model will not upgrade nor will Asus do anything with it's software/hardware to enable it to upgrade to windows 8.1.
Microsoft did look at all my logs relating to installation of 8.1 and couldn't conclude why it wouldn't upgrade. Those logs were given to the software experts for additional investigation. Since other brands of laptops have this same problem, a fix in the future may be coming. I recently reimaged my laptop with an known good working copy of windows 8.1 and during boot, it reported that the software couldn't work and gave the same error codes as before. Since an attempt to upgrades to windows 8.1 from 8.0 wipes out all your software and you have to reload, I will wait and observe the blogs until someone reports a successful upgrade to windows 8.1. Please repost if you find the magic wand to resolve this problem, good luck.