This is my first posting. I'm 71 and just built my first computer. I found this site while looking for a way to get my just-built computer to do anything!. After installing windows 8.1 it worked for about an hour then gave me a black screen with a blinking cursor. I couldn't use the keyboard of the mouse. I found a problem something like mine, tried the answer given and it worked! It involved repeatedly pushing the f8 key. As far as i'm concerned it might as well have been magic.
I'm going to post my next problem in the windows 8 forum and hope my lucky streak holds.
I hope I can help someone as I've been helped.