Hello mat stewart,
Welcome to the Microsoft Community!
It looks like you have a complex set of problems and they seem to be interrelated. I understand what is troubling you.
I noticed that you mentioned in your edit that your computer rolled back, and that there is a known issue in KB5034848: Windows 11 devices may experience problems during this process and the installation may roll back to 96%.
Please refer to this official document: February 29, 2024—KB5034848 (OS Builds 22621.3235 and 22631.3235) Preview - Microsoft Support
According to your description, you are unable to perform a restart of Explorer, probably due to a corrupt registry that prevents you from opening Task Manager, here are some options on how to fix Task Manager, if you haven't tried them, you can try these possible options:
- Repair Task Manager from the registry:
- Windows search "regedit" to open "Registry Editor".
- Then navigate to the following location:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies - If there is no item under "Policies", right-click on "Policies" and select "New" > "Item". "and name it System.
- Select "System" and right-click on the blank space in the right window. Select "New" and then select "DWORD (32-bit) Value". Name it DisableTaskMgr.
- Double-click DisableTaskMgr and set its value to 0, and then click OK.
Disclaimer: Generally, modifying registry subkeys or work group is intended for advanced users, administrators, and IT Professionals. It can help fix some problems, however, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For further protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click How to back up and restore the registry in Windows - Microsoft Support to view the article.
- Check if Task Manager is blocked from Group Policy
Windows search "gpedit.msc" to open the "Local Group Policy Editor".
Click User Configuration---Administrative Templates---System---Ctrl+Alt+Del Options---"Remove Task Manager" to confirm that it is set to "Not Configured" or "Disable with "Then click "Apply" and "OK".
- If the above actions do not fix Task Manager, you can try to re-register Task Manager:
Right-click on "Start" at the bottom left corner of your desktop and select "Windows PowerShell (Administrator)".
Copy and paste the following code and press "Enter":
Get -AppXPackage -AllUsers|Foreach {Add -AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest. xml"}
Then open "This Computer", select "View" and check "Hidden Items".
Then open c-drive>User>Username>AppData>Local, delete the TileDataLayer folder, and restart your computer to test.
- Also, I noticed that you have used iso repair, have you tried restoring to a restore point? If not, this is also an option to try so that you can restore to the previous setup state. You can refer to the "System Restore Point Restore" section at the bottom of this document, link below:
Recovery options in Windows - Microsoft Support
Hope this helps,please feel free to reply me if anything is unclear or if there are any further updates, thanks.
Best Regards ,
Morning | Microsoft Technical Support Community