I have a HP Envy dv7 which has recently developed an issue. During a boot with windows 8.1, near the end on the front screen the mouse keeps a circle rotating and the icons and screen jump every few seconds. This does not resolve and finish the boot.
I have Norton 360 on it. I was using a USB stick and have tried placing this in the same slot during boot but this makes no difference. Windows completed an update of two files at the time the problem occurred.
I have tried doing the hard reset as described on this site but it did not work for this problem. Tried using shift and F8 to go into safe mode at boot but this did not work.