Unable to type text in any of start (search func)

Please try creating a new user for test purposes. See if the symptoms are the same.

If they are, this is likely to be a Window issue.
If not, your user profile is corrupt or something is configured which causes this.

If logging in as a new user makes no difference you can also try a clean boot, and see if there's any change.

Hi, thanks, that's a useful outcome.

Since you see the same thing in a new user, but not in Safe Mode, that tells me it should be possible to identify this by a process of elimination.

I'm not certain what a 'filescanner' is. Do you perhaps mean running
SFC /SCANNOW
from an admin command prompt?

In a safe boot fewer items are started compared to a clean boot.
You can research this for yourself.

So now please try a clean boot and see if the same symptom appears.

You can find out how to do this from the internet, or from the Tutorial section here:
Perform a Clean Boot in Windows 10 to Troubleshoot Software Conflicts Windows 10 Performance Maintenance Tutorials
- Part 1.

Note: you may find it helpful as a convenience to set a System Restore point before setting things up for the clean boot, so using the restore point then lets you restore exactly the same state.
(The same could be achieved by backing up your registry and restoring it).

If you find typing is ok after a clean boot, then you can try enabling all services, checking again, then enable start-ups one by one until the symptom reappears.

@mrgeek- there's no need to do such an extensive procedure yet- it seems to be a start-up that is interfering.

As typing is ok in Safe Mode, the repairs provided by this- replacing some registry entries and system files- should not be applicable.

Please let the user try simply identify what is apparently) interfering with Windows. That is a much more trivial procedure.

If that is so, an in-place upgrade repair install will not fix this. Further, to recommend an in-place upgrade repair install at this time means you should determine which build (AU or CU) the user is using. Otherwise you could have them upgrading to the CU.

Ok, now the normal clean boot procedure only disables a number of basic items.

It would seem something is starting in a clean boot scenario that is not starting in Safe Mode.
If you have any idea of changes you made or that occurred before the problem appeared, this will help greatly.

I don't think I've yet asked if you have any System Restore points you can use. That's the first thing to try.

Otherwise:

Please download MS Sysinternals Autoruns (free) and install it. It needs to be run as admin.

This reads the registry and lists every item that starts up, from drivers and context menu entries to programs.

When you run it, you can see a lot of tabs. Each tab is a different class or group of items that start up; you can choose to view Everything, and the startups are listed in those groups.

Before you use this, I strongly recommend you back up your registry.

Now you need to carefully select items to disable.
Avoid anything related to MS.

You can disable a number of items, and check the effect.

This needs to be done carefully, and will probably take a number of attempts.

If you wish to disable a startup, simply untick its box.

I have searched for
how do I use autoruns
for you

Using Autoruns Tool to Track Startup Applications and Add-ons

Make Windows start faster with Autoruns - PC Advisor

There are also some youtube guides.
How To: Use Autoruns for Windows - YouTube