Thanks, Frank, for following this up. I was not able to solve the problem, so I bit the bullet and handed the PC in to customers service at the place where I had bought it. After 2-3 days I got it back. Soon after I had booted, the same driver power state failure happened again! I called the shop and learnt that what they had done was running some Windows tools and done some security updates. They had not reformatted. We agreed that I was to give the machine back next time I went to town, which was today.
In the meantime I had experienced several of those wanting to update, then reboot, and If I let it reboot, it reached 33% and then cut out, restored the previous version. Once there was another error, with a code that I wrote down and gave the support people when I was there about an hour ago. And the last thing that happened, last night, after trying to update and trying to go back to the previous version for something like 3 hours without success, I gave up and shut down and disconnected the PC. I didn't want to fuss more about it, since it is less than a year old and under warranty.
So, we'll see what happens... Luckily I have two laptops, one of them a Mac and one Windows.