Start menu not appearing after update + Explorer not starting

Hi, as a matter of routine, please run these basic checks before starting repairs:

a. check your disk - Hard Disk Sentinel (trial) - great text report- else freeware for SMART param checks e.g. Crystal Diskinfo, HD Tune
b. If ok run chkdsk c: /scan
and report the result. (That tests only- no fixes).

If ok..
Try creating a new user for test purposes, log in as that user, and check for the above problems.
Report any that are the same, and any that are not present.

This is an essential step to determine whether to try to fix your user profile, or to fix Windows.

I understand your build to be 1803. Depending on the above, if you see similar problems with the new user, and given the variety of problems, I suggest you do an in-place upgrade repair install (tutorial available) which keeps progs, data and most settings for which you will need a build 1803 iso (freely downloadable).

Yesterday, there was an update installed.

Just to be sure, please post the result of
Win key + r, winver


Note: do you use disk imaging routinely (e.g. Macrium Reflect - free/commercial) as is so often recommended here? If you did, you would have hte opportunity to restore your system to a previously good state (the date you created an image) without technical help.

However, you have lived with problems for too long now for that to be useful at this point, even if you did use it. But for the future, very strongly recommended.

Thanks.

Given what you report, suggests an in-place upgrade repair install is appropriate.

For that you need an iso of your 1803 build (freely available, question often answered on how to get one (e.g. via heidoc's site, via the Microsoft media creation tool, or see a tutorial here or posts answering this question).

Search
Windows 10 Tutorial Index
- the tutorials section for in-place and you find
Repair Install Windows 10 with an In-place Upgrade
or you could use Google e.g.

It's simpler than it looks to do it. I suggest not accepting updates during the 'upgrade repair', and create a disk image beforehand, just in case (Macrium Reflect- free) - lots of help/guidance/tutorials/videos on using that. You'll need a large enough external disk e.g. for the base image file.

If I understand the process of doing that, I would lose the installed applications on my PC!!

No no no. Think. Do you lose programs when upgrading from one build to another? Are you afraid of upgrading to a higher build? It's the same process. You will not lose programs, apps or personal data.

Have you read the tutorial?

See section 12. (The paras on Refresh and Reset at the beginning are not about an in-place upgrade repair. They refer to different options. You probably read those).

Make sure you create a disk image before starting as a matter of routine security and good practice.

Remember you also said you can't create a new account. So you have some basic problems.