I tried to install the Windows 8.1 update 1 (KB 2919355) today and it left my computer in an unbootable state (I can't even boot to safe mode). It shows the Windows logo and circles and after that, it sits at a black screen with the cursor and
wifi indicator appearing periodically. I thought it created a system restore point but it never did. I managed to boot to recovery but from there, I attempted to run a startup repair and sfc /scannow and I had no luck whatsoever. I really don't want to do
a clean install because I just did one about 3 weeks back and just recently got everything back on there. The computer did not originally come with Windows 8 as it was upgraded to it from Windows 7.