HELP - my pc wont reboot - User Profile Service fails at login

[#1]

@ReedRichards   I've done as you suggested - ran Windows Update, then created a new system image on a spare HDD, which is external to my pc. That leads to a few questions:-

1. Do I have to create a new repair disk every time I create a new system image, or would the repair disk I created a few days ago for my previous image be perfectly acceptable for this latest image? I have created a repair disk this time

2. If in the future I create yet another image, can I use that same HDD without deleting the image I have just created?

3. If the answer to 2. is Yes, how do I differentiate between the two images? Should I rename the first image before creating the next image? If I rename the first image, will the repair disk still work with it (in case the next image doesn't work for some reason)?

Thanks - have a good weekend

[#2]

@penneck there are lots of different ways you can crate a system image.  A long time ago i bought a program called Acronis True Image; I have always used that so I'm not really familiar with the Windows built-in system.  Thus I myself cannot answer your questions with much certainty.  Perhaps someone else can help?

1. I imagine you only need one Repair Disk as the function of this is to boot the computer and initiate the restoration process.
2. If this works the same way as the rest of the Windows 7 backup then the answer is yes.
3. If it works the same way as the rest then the default option is to restore the most recent backup but you can choose an earlier one .   

[#3]

Thanks very much ReedRichards

[#4]

I 've just had a repeat of the problem that started this series of posts off two weeks ago. Fortunately, a Safe Mode start and then look at System Restore Points revealed there was a Restore Point from two days ago. I used that, and the pc now boots up correctly, but what the hell is going on? I have never had this problem before two weeks ago

[#5]

You don't have any control of what the Windows update dumps onto your machine - it doesn't tell you what its going to do and certainly doesn't ask for your permission.

So you are just running a black box which doesn't reveal what's happening inside.

[#6]

I have seen an outbreak of "temporary profile" login errors; not quite the same thing as the error you originally reported although along the same lines.  Suspicion online is that Microsoft Security Essentials (Windows Defender on 8/10) is malfunctioning and is responsible for these.